Sample records for celulas troncales autologas
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Las células troncales pluripotenciales en la terapia celular
J.A. Gámez Escalona; N. López Moratalla
2014-01-01
Las células con pluripotencialidad inducida (iPS) son un nuevo tipo de célula troncal derivada de células somáticas humanas, mediante reprogramación con factores de transcripción. Estas células iPS tienen características de las células troncales embrionarias, como la capacidad de convertirse en todos los tipos de células diferenciadas del organismo. A corto plazo, las células de pacientes reprogramadas están siendo útiles para crear modelos celulares de enfermedades, en las que estudiar los p...
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Células troncales mesenquimales: historia, biología y aplicación clínica
Flores-Figueroa, Eugenia; Montesinos, Juan José; Mayani, Héctor
2006-01-01
En los últimos años, el tema de las células troncales o células madre ha llamado la atención a varios sectores de la sociedad por diversas razones. Desde el punto de vista básico, constituyen un inmejorable modelo para estudiar los mecanismos de diferenciación y autorrenovación celular. Sin embargo, es sin duda, su potencial en la terapia celular y la medicina regenerativa lo que ha disparado la generación de estudios y conocimientos sobre este tema. Las células troncales mesenquimales perten...
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Epitelización inducida por células troncales derivadas del tejido adiposo
Directory of Open Access Journals (Sweden)
M. Meruane
2014-06-01
Full Text Available El tratamiento de lesiones con pérdida de tejido cutáneo ha mejorado notablemente con el advenimiento de la bioingeniería tisular. Una alternativa en desarrollo es la utilización de sustitutos dérmicos combinados con células troncales derivadas del tejido adiposo autólogo. Estudios previos nos muestran que con esta técnica es posible optimizar la angiogénesis y la síntesis de colágeno, sin embargo potenciar la epitelización es un tema pendiente por resolver. En el presente estudio evaluamos la progresión y diferenciación epitelial en un período de tiempo prologando. Obtuvimos las células troncales a partir del tejido adiposo (ASC de la región inguinal de 4 ratas Sprague Dawley. Cultivamos las células frescas en una matriz de Integra® durante un período total de 48 horas, y las marcamos con un vector lentiviral-GFP (proteína fluorescente verde. Posteriormente, injertamos en las mismas ratas la matriz dérmica con células troncales y un implante contralateral sin células, como control. A las 4 semanas, evaluamos el avance epitelial mediante planimetría de superficie e histología. Los resultados macroscópicos muestran que el cierre de la herida por contracción de los bordes no tiene diferencias significativas (82,63% ± 3,4% vs. 80,66% ± 3,89%; p=0,08, pero el cierre por epitelización fue significativamente mayor en el lado intervenido con ASCs (93,47% ± 5,98% vs. 79,88% ± 6,28%; p=0,0028. Todas las muestras obtuvieron tinción positiva para el anticuerpo anti-citoqueratina 34βE12 y el avance epitelial lineal cuantificado por microscopía resultó significativamente mayor en el lado con ASCs (6408 ± 275μm vs. 5375 ± 250μm; p < 0,001. Identificamos las células GFP positivas formando parte de la dermis regenerada, no así en la epidermis. En conclusión, las células troncales derivadas del tejido adiposo autólogo sembradas en una matriz de Integra® aumentan la formación epitelial significativamente
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Celulas solares e sensores de filme fino de silicio depositados sobre substratos flexiveis =
Pinto, Emilio Sergio Marins Vieira
Celulas solares flexiveis de filmes finos de silicio sao geralmente fabricadas a baixa temperatura sobre substratos de plastico ou a mais elevadas temperaturas sobre folhas de aco. Esta tese reporta o estudo da deposicao de filmes finos sobre diferentes substratos de plastico, transparentes e coloridos, para celulas solares do tipo sobrestrato e substrato, respectivamente. Como objetivo co-lateral, os filmes dopados depositados sobre plastico foram usados como sensores de deformacao, utilizando as suas propriedades piezo-resistivas. Elevadas taxas de deposicao dos filmes de silicio depositados sobre plastico foram obtidas a baixa temperatura do substrato (150ºC) por rf-PECVD. A influencia de diferentes parametros de deposicao sobre as propriedades e taxa de deposicao dos filmes resultantes foram estudados e correlacionados. Celulas solares de filmes finos de silicio amorfo e microcristalino foram desenvolvidas a baixas temperaturas sobre plasticos. Eficiencias de 5 - 6.5% foram alcancadas para as celulas amorfas e 7.5% para as celulas microcristalinas. Efeitos de aprisionamento da luz foram estudados atraves da texturizacao por ablacao laser de substratos de plastico e corrosao umida de TCO sobre plastico. Filmes finos de silicio microcristalino, depositados por HW-CVD, com fator piezoresistivo de -32.2, foram usados para fabricar sensores de deformacao em uma membrana plastica muito fina (15 μm). Estruturas de teste em textil e a miniaturizacao dos sensores piezoresistivos depositados sobre substratos flexiveis de poliimida foram abordados.
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Células troncales rejuvenecidas y el final de la clonación
Natalia López Moratalla
2007-01-01
El pasado 7 de junio la revista Nature reconoce imposibilidad de obtener células troncales para investigación, mediante el inefi ciente proceso de transferencia del núcleo de una célula de adulto a oocitos humanos. Al mismo tiempo acepta que ese tipo celular, tan buscado y sometido a fraude, se ha obtenido limpiamente por el procedimiento contrario; esto es, reprogramando hacia atrás, mediante ingeniería genética, una célula de adulto. Se estrena para el caso nueva revista Cell Stem Cell y Na...
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Epitelización inducida por células troncales derivadas del tejido adiposo
M. Meruane; S. Benítez; M. Rojas; A. Sagredo; K. Marcelain; B. Villalobos
2014-01-01
El tratamiento de lesiones con pérdida de tejido cutáneo ha mejorado notablemente con el advenimiento de la bioingeniería tisular. Una alternativa en desarrollo es la utilización de sustitutos dérmicos combinados con células troncales derivadas del tejido adiposo autólogo. Estudios previos nos muestran que con esta técnica es posible optimizar la angiogénesis y la síntesis de colágeno, sin embargo potenciar la epitelización es un tema pendiente por resolver. En el presente estudio evaluamos l...
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Gomes, Maria Manuela Estima
tecido osseo, uma vez que estas celulas podem ser facilmente recolhidas do proprio paciente a tratar por metodos nao-invasivos (bioppsia) e em quantidades suficientes. Alem disso, tratando-se de uma fonte de celulas autologas (obtidas do proprio paciente) permitem evitar os riscos de transmissao de doencas contagiosas e/ou de rejeicao pelo sistema imunologico. • Estudo da influencia das condicoes de cultura in vitro geradas por um bioreactor de perfusao (em comparacao com os metodos tradicionais de cultura em condicoes estaticas) no desenvolvimento dos materiais hibridos, compostos pelas celulas e scaffolds, assim como as interaccoes do ambiente proporcionado por este sistema de cultura com as diferentes estruturas/arquitecturas e porosidades dos scaffolds utilizados. Estes objectivos convergem para o objectivo geral desta tese que consistiu no desenvolvimento de uma terapia de engenharia do tecido osseo alternativa as existentes e com potencial para vir a ser posteriormente utilizada na pratica clinica. Este objectivo foi avaliado atraves do estudo da funcionalidade dos materiais hibridos obtidos em diferentes condicoes de cultura in vitro (e utilizando diferentes scaffolds), partindo do principio que o sistema de perfusao poderia eventualmente superar as limitacoes de difusao tipicas dos sistema de cultura estatica e simultaneamente proporcionar estimulos mecânicos as celulas, semelhantes aos encontrados em condicoes fisiologicas. (Abstract shortened by ProQuest.).
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Villavicencio Barriga, Verónica Dayana
2012-01-01
Este estudio determinó la Prevalencia de Desnutrición y sus determinantes sociodemográficos, de condición clínico-quirúrgica, hospitalización y calidad de atención en el Hospital Darío Machuca Palacios la Troncal. Se realizó un estudio no experimental de tipo transversal donde se encuestaron 150 pacientes mayores de 18 años, con una historia clínica abierta y diagnóstico definido. El estudio se condujo en 2 fases. La primera fue una auditoría de la historia clínica, con el que se determinó...
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Energy Technology Data Exchange (ETDEWEB)
Rivera, E; Cricco, G; Martin, G; Cocca, C; Bergoc, R M [Buenos Aires Univ. (Argentina). Facultad de Farmacia y Bioquimica; Croci, M [Fundacion Dr. Ernesto Crescenti, Buenos Aires (Argentina)
1999-12-31
los mayores danos despues de la irradiacion de cuerpo entero. En roedores, dosis de 2 a 10 Gy, producen la muerte entre 10 y 30 dias post-irradiacion, siendo el pancreas uno de los organos mas tolerantes a la radiacion ionizante. En nuestro laboratorio hemos irradiado lotes de ratas Sprague-Dawley adultas, de entre 360 y 420 g de peso, con una fuente de cesio 137 de 1,1 x10{sup 16} Bq con 2, 5, 6, 7, 8, 10, 12 y 15 Gy, empleandose 8 animales por dosis. La {sup 30}DL{sub 50} resultante fue de 7,14 Gy. Todos los pancreas fueron removidos cuando los animales murieron o bien cuando los sobrevivientes fueron sacrificados a los 60 dias post-irradiacion. Especimenes de 3-5 mm fueron fijados en formol-buffer, cortes de 3-4 {mu}m fueron tenidos con hematoxilina-eosina y observados microscopicamente. A dosis de 2-5 Gy no se observaron danios histologicos. A dosis mas altas, en los animales muertos a los 4-5 dias post-irradiacion se evidencio congestion capilar y en los sobrevivientes, afluencia de linfocitos en la periferia de los islotes de Langerhans. Por otra parte, se caracterizaron `in vitro` los parametros de radiosensiblidad D{sub 0} y N de celulas malignas PANC-1 derivadas de pancreas humanos, que retienen las caracteristicas tipicas de celulas ductales diferenciadas; las celulas se mantuvieron en medio RPMI 1640 suplementado con suero fetal bovino al 10%, en estufa a 37 grados C, 5% de CO{sub 2} y humedad adecuada. Las celulas se dejaron crecer a 70-80% de confluencia y en esas condiciones se las irradio con la misma fuente de cesio 137 con: 0,5; 1; 1,5; 2; 2,5; 3; 5; 8; 10; 12; 15 y 18 Gy. Los resultados obtenidos fueron: N=2 y D{sub 0}=0,75 {+-}0,12 Gy. Los resultados obtenidos permitieron caracterizar el tipo de lesiones histologicas a altas dosis y la radiosensibilidad de las celulas PANC-1. (autor)
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Villarroel, Mariana; Speight, Paul M.; Barrett, A. William
2005-01-01
El descubrimiento de que el epitelio escamoso estratificado que cubre la mucosa oral podia expresar moleculas del Complejo Mayor de Histocompatibilidad clase II en varias condiciones patologicas de tipo inflamatorio abrio la posibilidad de que los queratinocitos orales sean celulas inmunologicamente activas, las cuales pueden funcionar con .celulas presentadoras de antigenos'ñ. Para una efectiva activacion de los linfocitos T, las celulas presentadoras de antigenos requie...
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USE OF EMBRYONIC STEM CELLS TO TREAT SEVERE EYE DISEASES
JUSTO AZNAR; JULIO TUDELA
2016-01-01
Antecedentes: El uso de células troncales constituye una de las principales posibilidades terapéuticas en el área de la medicina regenerativa. Recientes ensayos clínicos utilizando células derivadas de troncales humanas, muestran resultados esperanzadores, aunque estos deben ser valorados con la necesaria cautela. Discusión: Algunos medios de comunicación han divulgado resultados de estos ensayos sin la debida prudencia, creando quizá expectativas que no se corresponden con...
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Directory of Open Access Journals (Sweden)
Fernanda Mafra Cajú
2011-04-01
Full Text Available The Sertoli cell has fundamental importance to the development andmaintenance of spermatogenesis, as well as it has a directly proportional numerical relationship to sperm production. The proliferative period of this cell in rats occurs between 13 days pre-natal and 21 days pos-natal, when is established the final population in adult animals. The Leydig cell can modulate the Sertoli cell proliferation during fetal and neonatal periodƒn throughƒnƒnƒÒ-endorphin. The manipulation of opioidergic system can promote changes in parameters related to development of nervous, endocrine andreproductive systems. By the way, the main purpose of this present work was to compare the effects of the blockade of opioid receptor blocking in Sertoli cells using naltrexone (50 mg kg-1 during fetal and neonatal period in Wistar rats. According to the results, themanipulation of opioidergic system during pre-natal period reduced the total length of seminiferous tubule and Sertoli cell population in adult rats, but sperm production was normal because this cell has had a compensatory response for spermatozoids support capacity.As celulas de Sertoli tem fundamental importancia para o desenvolvimento e manutencao da espermatogenese, bem como possuem uma relacao numerica diretamente proporcional com a producao espermatica. O periodo proliferativo destas celulas em ratos ocorre entre 13 dias pre-natal e 21 dias pos-natal, resultando na definicao da populacao decelulas de Sertoli nos animais adultos. As celulas de Leydig podem modular a proliferacao das celulas de Sertoli durante o periodo fetal e neonatal por meio da ƒÒ-endorfina. A manipulacao do sistema opioidergico durante esta fase pode promover alteracoes em parametros relacionados com o desenvolvimento dos sistemas nervoso, endocrino ereprodutivo. Em virtude disto, o objetivo do presente trabalho foi comparar os efeitos do bloqueio de receptores opioides nas celulas de Sertoli, utilizando o naltrexone (50 mg kg
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Energy Technology Data Exchange (ETDEWEB)
Gavosto, F. [Istituto di Clinica Medica Generale e Centro di Studi Fisico-Biologici, Universita de Turin, Turin (Italy)
1962-02-15
. L'auteur examine ensuite la diminution et la dissociation du metabolisme de l'ARN et des proteines, dans les cellules de sujets atteints de leucemie aiguee, par rapport aux anomalies bien connues que presente le processus de maturation de ces cellules. (author) [Spanish] El autor examina las ventajas que presenta el empleo de los compuestos marcados con tritio en la tecnica autorradiografica. En efecto, los electrones emitidos por el tritio tienen una energia maxima de 0,018 MeV, que corresponde, aproximadamente, a un alcance de 1 miera en una emulsion fotografica y permiten, por lo tanto, lograr el maximo poder de resolucion al nivel celular y subcelular. Ello es particularmente util para estudiar fenomenos metabolicos en tejidos que se componen, como en el caso de la medula osea, de celulas de varios tipos en diversos estados de diferenciacion. Esta tecnica se ha aplicado al estudio del metabolismo de los acidos nucleicos y de las proteinas en las celulas normales y leucemicas de la medula osea. El metabolismo del acido desoxirribonucleico se ha estudiado utilizando un precursor especifico, la timidina-{sup 3}H. Comparando los elementos normales y leucemicos que han alcanzado un grado de madurez analogo, se han observado diferencias significativas en el porcentaje de celulas marcadas. Especialmente, en los casos de leucemia aguda, se ha comprobado que la incorporacion de timidina en las celulas leucemicas disminuye muy notablemente. Se estima que estos resultados constituyen una prueba de que la capacidad de proliferacion de estas celulas disminuye en comparacion con la de los mieloblastos normales. Por este mismo procedimiento, se ha estudiado el metabolismo del acido ribonucleico y de las proteinas, utilizando como precursores uridina-{sup 3}H, leucina-{sup 3}H y fenilalanina-{sup 3}H. Actualmente, en biologia celular se admite sin reservas la existencia de una estrecha relacion entre el metabolismo del acido ribonucleico y el de las proteinas. Ademas, se ha
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ORF Alignment: NC_002570 [GENIUS II[Archive
Lifescience Database Archive (English)
Full Text Available NC_002570 gi|15613166 >1ceo0 7 334 45 353 9e-20 ... dbj|BAB04322.1| endo-beta-1,4-glucanase (celula...se B) [Bacillus halodurans C-125] ... ref|NP_241469.1| endo-beta-1,4-glucanase (celulas...e B) ... [Bacillus halodurans C-125] pir||C83725 ... endo-beta-1,4-glucanase (celulase B) BH06
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Almendros Marqués, Nieves; Delgado Molina, Esther; Tamarit Borrás, Meritxell; Berini Aytés, Leonardo; Gay Escoda, Cosme
2007-01-01
Objetivos: Evaluar las posibles diferencias existentes en cuanto a la deformación del bisel de dos tipos de aguja de igual longitud y calibre externo, pero de distinto diámetro interno, durante el bloqueo troncal del nervio dentario inferior. Diseño del estudio: Cuatro operadores de similar formación quirúrgica realizaron el bloqueo troncal del nervio dentario inferior y la anestesia infiltrativa del nervio bucal para proceder a la extracción quirúrgica o convencional del tercer molar infe...
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Pericuesta Camacho, Eva
2011-01-01
La presente tesis está compuesta por tres artículos científicos publicados (Pericuesta et al., 2006; Ramirez et al., 2006; Ramírez et al., 2007) y un último trabajo realizado para completar el análisis de las células troncales en tejidos adultos. La importancia de las células troncales ha crecido enormemente en las últimas décadas debido al gran potencial que presentan para tratar enfermedades hasta hoy incurables como el Parkinson, la diabetes tipo I, la enfermedad de Alzheimer, esclerosis m...
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Therapeutic Effect of Exosomes on Ischemic Stroke in Experimental Animals
Carvallo, P; Astudillo, P
2016-01-01
La posibilidad de que los exosomas funcionen como una nueva forma de comunicación intercelular para establecer y mantener circuitos cerebrales está comenzando a ser explorada. Los exosomas son liberados desde células e interactúan con otras células receptoras para mediar cambios fisiológicos. Todas las células cerebrales liberan exosomas incluyendo las celulas madre neuronales, las neuronas, astrocitos, microglia, oligodendrocitos y las celulas endoteliales. El objetivo de esta revisión es re...
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Energy Technology Data Exchange (ETDEWEB)
Arce Vargas, Frederick [Costa Rica
2006-07-01
of these cells to different chemotherapeutic agents. Survivin might decrease the answer of treatment by to be anti-apoptotic and even to change the apoptosis by other forms of cellular death (necrosis, mitotic catastrophe, etc.) doing that therapy be less efficient. Hep3B cells were sensitized with ATRA before to be treated with 5-FU and it was observed a more cytotoxicity than when every drug was used separately. Also there were required concentrations lower of both agents to produce cellular death. This effect didn't see with HepG2 cells. Although retinoids seem to be promising in the hepato carcinoma treatment, it must do more studies to improve the bioavailability and to decrease the unspecific toxicity of these drugs, including combinations with other agents, use of liposomes or synthesis of compounds with effects more selective that might be even directed to certain specific routes of cellular death. (author) [Spanish] Dos lineas celulares de cancer de higado (Hep3B and HepG2) se incubaron durante diferentes periodos de tiempo con varias concentraciones de dos isomeros del acido retinoico (ATRA y 13-cis AR) y con los agentes quimioterapeuticos 5-FU, cisplatino y paclitaxel. Se determino si estas sustancias inducian citotoxicidad, apoptosis y si modificaban la expresion de diferentes genes relacionados con la muerte celular por apoptosis, en parte para poder explicar la resistencia del carcinoma hepatocelular a estas drogas. Las celulas HepG2 mostraron mayor resistencia que las celulas Hep3B a las 72 horas de tratamiento, tanto el ATRA como el 13-cis AR fueron toxicos. Tambien se demostro que producian apoptosis en las dos lineas celulares. Este tipo de muerte celular parece estar mediada por una disminucion en la concentracion de Bcl-xL en las celulas Hep3B tratadas con ambos retinoides y un aumento en la concentracion de Bax en las celulas HepG2 tratadas con 13-cis AR. Se observo proteolisis de procaspasas 3 y 8 en las celulas Hep3B, sugiriendo activacion de
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Energy Technology Data Exchange (ETDEWEB)
Von Borstel, R. C. [Biology Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
1963-09-15
en calculant la viabilite des gametes, au moyen d'experiences comparatives avec des populations non irradiees ainsi que par l'examen histologique des gonades. (author) [Spanish] Las radiaciones y los productos quimicos mutagenos pueden matar las celulas de modos diversos, a saber: mediante la induccion de uno o varios tipos de elementos letales dominantes, por inactivacion directa de una funcion, como la produccion de esperma, y por procedimientos geneticamente indefinibles de exterminacion que pueden o no estar relacionados con la letalidad dominante intrinseca. Por otra parte, los productos quimicos mutagenos parecen provocar un curioso aumento de la capacidad fertilizante de la esperma. La radiosensibilidad varia segun las diferentes etapas de la oogenesis y de la espermatogenesis, y las celulas pasan por fases en que dicha sensibilidad llega a ser 50 veces superior o inferior que en otras. En la medida en que distintas especies de dipteros, himenopteros y coleopteros son comparables, puede observarse una sorprendente analogia en la radiosensibilidad, tanto segun las etapas como segun las dosis. La radiosensibilidad de las celulas germinales del gusano de seda Bombyx mori (Lepidopt. ) parece similar en muchos aspectos a la de los insectos de otros ordenes, pero en cambio hay grandes diferencias en cuanto a los tipos de elementos letales dominantes que en el pueden inducirse. Las especies con mecanismos geneticos atipicos (por ejemplo, el sistema lecanoideo del Planococcus citri (Hemipt. ; Coccidae) constituyen casos especiales y su radiosensibilidad varia considerablemente en relacion con la de otras especies. Para la lucha contra los insectos por el metodo de irradiacion de los machos, la creacion de un elemento letal dominante ofrece en las especies donde las copulas son multiples las mismas ventajas que en las especies que copulan solo iva vez. La inactivacion de la esperma y la exterminacion de las celulas gonadicas pueden considerarse como casos de autentica
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Institucional: Departamento de Ciencias Complementarias
Revista Institucional de la Facultad de Ciencias Económicas
2010-01-01
El Departamento de Ciencias Complementarias involucra las cátedras de las áreas jurídica, matemática y humanística que, sin ser troncales, coadyuvan a la formación integral del futuro profesional en ciencias económicas.
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Presentaciones Powerpoint de Psicología Criminal
Herranz Bellido, Jesús; Romo Donaire, Ana María; Albaladejo-Blázquez, Natalia; Jarque Llamazares, Livia
2008-01-01
Estas 16 presentaciones Powerpoint han sido elaboradas para servir a los estudiantes como un breve resumen de los contenidos teóricos que constituyen el programa de la asignatura Psicología Criminal, que se imparte como asignatura troncal en la Licenciatura de Criminología de la Universidad de Alicante.
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2012-07-12
J Gastroenterol 2010;16:302 4. 3. Meyer CT, Troncale FJ, Galloway S, Sheahan DG. Arteriovenous malformation of the bowel: an analysis of 22 cases and...Becker GJ, Park HM, O’Connor KW, Tarver RD, Scott JA, Jackson VP, Lappas JC, Broadie TA, Holden RW. Portal hypertension due to jejunal vascular
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Directory of Open Access Journals (Sweden)
C. Magarinos Torres
1934-02-01
Full Text Available Vesiculas e pustulas contendo numerosas inclusões citoplasmicas nas celulas epidermicas, foram regularmente produzidas no macaco (Macacus rhesus, quer com o virus do alastrim, quer com o da vacina, após inoculação endovenosa e sem previa escarificação. O virus do alastrim parece menos virulento para essa especie de macaco que o da vacina. Ao passo que 12 macacos rhesus injetados por via endovenosa com sete amostras diferentes de virus do alastrim, após apresentarem com regularidade um infecção experimental, sobreviveram e se conservaram em boa saúde, a injecção endovenosa do virus da vacina recentemente preparado (polpa bruta produziu a morte em 2, dentre 4 animais experimentados. 2. - Foram notadas diferenças pequenas, mas nitidas, na morfologia das inclusões do alastrim e da vacina, em material fixado no liquido de Helly, incluido em parafina e corado pela hematoxilina-eosina. Dizem elas respeito ao numero de inclusões encontradas em cada celula epidermica e às suas reações de coloração. 3. - As inclusões do alastrim, quando apresentam grandes dimensões, conservam-se unicas ou solitarias no citoplasma das celulas epidermicas do macaco rhesus, e coram-se em tonalidade que varia do azul escuro ao cinzento-azulado. Comtudo, em celulas que sofreram necrose, ou naquelas contendo 2 a 4 inclusões de pequenas dimensões, por vezes elas se mostram coradas em roseo. 4. - As inclusões da vacina, quando em faze adeantada de desenvolvimento, são multiplas nas celulas epidermicas do macaco rhesus e mostram, regularmente, uma policromatofilia caracteristica.1. - Vesicles and pustules containing numerous cytoplasmic inclusion bodies within the epidermal cells were regularly produced in monkeys (Macacus rhesus by intravenous inoculation either of alastrim virus or of recently prepared vaccine emulsion, no previous scarifications being required. Alastrim virus seems less virulent for this species of monkey than the virus of vaccinia is
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Energy Technology Data Exchange (ETDEWEB)
Hampton, J. C. [Division of Experimental Biology, Baylor University College of Medicine, TX (United States); Quastler, H. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)
1962-02-15
dans la cellule. Les travaux presentes dans ce memoire demontrent qu'il est possible d'etudier au microscope electronique des coupes ultrafines de cellules marquees, de recuperer l'echantillon apres avoir pris des micrographies electroniques convenables, de l'enduire d'une emulsion suffisamment epaisse pour obtenir une autoradiographie, mais tout de meme assez mince pour permettre un nouvel examen au microscope electronique et obtenir des images micrographiques des autoradiographies deja faites. L'emulsion autoradiographique a ete appliquee comme suit: formation d'une mince pellicule sur une petite boucle de fil metallique plongee dans l'emulsion liquide, puis transfert de la pellicule par passage de la boucle sur l'echantillon monte, fixe a l'extremite d'une chevillette en plastique. On peut effectuer un controle satisfaisant en prenant, lorsqu'on fait les coupes, une coupe d'un demimicron apres chaque coupe ultrafine en la montant sur une lamelle de verre et en appliquant les techniques autoradiographiques classiques. En raison de la fragilite des coupes ultrafines, le nombre d'autoradiographies reussies est tres faible. Malgre cet inconvenient, on peut esperer qu'avec une plus grande experience et un perfectionnement des techniques, cette methode aidera a mieux comprendre les processus des cellules vitales. (author) [Spanish] Merced al elevado grado de resolucion que puede alcanzarse actualmente por observacion de cortes de celulas en el microscopio electronico, resulta posible estudiar algunos de los procesos intracelulares que conducen a la sintesis de las proteinas. La especificidad de la incorporacion de timidina tritiada en la molecula de acido desoxirribonucleico permite seguir detenidamente el desarrollo del proceso en funcion del tiempo y su localizacion dentro de la celula. Los trabajos descritos en la presente memoria demuestran que es posible estudiar por microscopia electronica cortes ultrafinos de celulas tritiadas, retirar la muestra una vez que se han
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"Discovering the Cell": An Educational Game about Cell and Molecular Biology
Spiegel, Carolina N.; Alves, Gutemberg G.; Cardona, Tania da S.; Melim, Leandra M. C.; Luz, Mauricio R. M. P.; Araujo-Jorge, Tania C.; Henriques-Pons, Andrea
2008-01-01
The role of games within education becomes clearer as students become more active and are able to take decisions, solve problems and react to the results of those decisions. The educational board game "Discovering the Cell" ("Celula Adentro"), is based on problem-solving learning. This investigative game attempts to stimulate…
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Energy Technology Data Exchange (ETDEWEB)
Bond, V. P.; Feinendegen, L. E.; Cronkite, E. P. [Medical Research Centre, Brookhaven National Laboratory, Upton, Long Island, NY (United States)
1962-02-15
maniere que l'ADN. L'ARN et l'ADN de formation recente ne se diluent dans les cellules qu'a la faveur de la division cellulaire. (author) [Spanish] Los autores han estudiado el metabolismo de los acidos desoxirribonucleico y ribonucleico utilizando timidina tritiada (timidina-{sup 3}H), un precursor especifico del acido desoxirribonucleico, y citidina tritiada (citidina-{sup 3}H), un precursor comun de los acidos ribonucleico y desoxirribonucleico. Empleando citidina-{sup 3}H se determino autorradiograficamente la incorporacion diferencial por celula en los acidos ribonucleico y desoxirribonucleico, asi como en el espacio soluble. La misma determinacion se efectuo empleando metodos autorradiograficos y quimicos en el caso de poblaciones celulares, mediante extraccion diferencial aplicando un tratamiento apropiado con acido perclorico. Los estudios preliminares sobre renovacion realizados en celulas de HeLa con citidina-{sup 3}H pusieron de manifiesto la funcion precursora del acido ribonucleico nuclear respecto del acido ribonucleico citoplasmatico. La conservacion y distribucion del indicador en la fraccion acido ribonucleico es compatible con una mayor estabilidad de las macromoleculas de dicho acido. Asimismo, la incorporacion continua del indicador en la fraccion acido desoxirribonucleico es compatible con la presencia de un precursor de dicho acido en las ultimas fases de la sintesis. Fenomenos analogos se observaron en las celulas no maduras de la medula osea de la tata, estudiadas durante los dias consecutivos a la administracion de citidina-{sup 3}H por via intravenosa. La actividad del tritio en la fraccion soluble en acido y en las fracciones ARN y ADN se evaluo por metodos quimicos y autorradiograficos. Se comprobo que las tres curvas son paralelas desde el dia que sigue al de inyeccion y paralelas asimismo a las curvas de actividad del tritio en el acido desoxirribonucleico, cuando este se marca con timidina- {sup 3}H. La velocidad de disminucion de la
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Directory of Open Access Journals (Sweden)
José Garcia Ribeiro Abreu Júnior
2013-01-01
Full Text Available Este editorial apresenta a revisao cientifica sobre o premio Nobel de Fisiologia e Medicina de 2012 conferido aos pesquisadores Jonh Gurdon e Shynia Yamanaka. No editorial e discutido com se chegou a descoberta sobre a reprogramacao do genoma e seus impactos na medicina do futuro baseada em celulas tronco.
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Energy Technology Data Exchange (ETDEWEB)
Narvaez Perez, Camilo; Garcia Conejo, Dante Aristoteles [Comision Federal de Electricidad, Centro Nacional de Control de Energia, Area de Control Occidental, Zapopan, Jalisco (Mexico)]. E-mail: camilo.narvaez@cfe.gob.mx; camilo.narvaez@univa.mx; Ramirez Peredo, Patricia [Universidad de Guadalajara, Guadalajara, Jalisco (Mexico)]. E-mail: patyrape@hotmail.com; Blanco Gomez, Cesar Eduardo [Comision Federal de Electricidad, Centro Nacional de Control de Energia, Area de Control Occidental, Zapopan, Jalisco (Mexico)
2013-03-15
The growing power demand of users, who make loads of power systems, causes the components of such systems operating near its operating limits. And the transmission line, being the most common component in these, requires a thorough analysis in regard to the probability of three-phase shots and monopolars reclosing, considering thunderstorms, the demand system time, the flows circulating in lines, maintenance on other lines and other imponderantes. This research analyzes the normal probability of occurrence of shots in the 400 kV core network of the Area de Control Occidental, CFE and its impact on studies conducted prior to the maintenance. We intend to use the methodology in the Comision Federal de Electricidad and results can be validated with data from previous years, based on a pseudo shots forecast in a given period. [Spanish] La creciente demanda de energia electrica de los usuarios que componen las cargas de los sistemas electricos de potencia, provoca que los componentes de dichos sistemas funcionen cerca de sus limites operativos. Y la linea de transmision, al ser el componente mas comun en estos, requiere de un analisis minucioso en lo que respecta a la probabilidad de disparos trifasicos y recierres monopolares, considerando tormentas electricas, la demanda horaria del sistema, los flujos que circulan en las lineas, los mantenimientos en las demas lineas y demas imponderantes. En esta investigacion se analiza la probabilidad normal de ocurrencia de disparos en la red troncal de 400 kV del Area de Control Occidental y su impacto en los estudios que se realizan previos a los mantenimientos. Se pretende utilizar la metodologia en la Comision Federal de Electricidad, y los resultados pueden ser validados con datos de los anos anteriores, ya que se hace un pseudo pronostico de disparos en un periodo dado.
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2011-01-01
La asignatura de Cirugía Bucal con código de la asignatura 34715 forma parte de la materia troncal Patología médico-quirúrgica en la Licenciatura de Odontología, de periodicidad anual. El programa se imparte a los alumnos de 3º de Odontología de la Facultad de Medicina y Cirugía Bucal de la Universidad de Valencia.
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Chest wall reconstruction with autologas rib grafts in dogs and report of a clinic case.
Tunçözgür, B; Elbeyli, L; Güngör, A; Işik, F; Akay, H
1999-09-01
Nowadays, in chest wall reconstruction prosthetic materials are generally used. However, the rejections of prosthetic materials and infections frequently occur in chest wall reconstruction, especially after radiotherapy or resection that is performed due to infections. We used 10 mongrel dogs and performed resections of 8 cm diameter on their chest walls. In the reconstruction of these defects, in five of the subjects, we used two free rib grafts with periosteum to be resected from the contralateral side and in other five subjects, we used free rib grafts without periosteum. After this experimental study, sternal resection was performed in a 24-year-old man because of sternal osteomyelitis. First to obtain rib grafts with periosteum, partial resection was performed to 5th, 7th, and 9th ribs of the lateral left side. After, total sternal resection, end to end anastomosis was performed to the 2nd, 3rd, 4th and 5th anterior ends of the ribs. Autogeneous rib grafts were found to be enough to provide chest wall stabilization. The contralateral autogeneous free rib grafts can successfully be used in reconstruction of wide chest wall defects. This method is found to be effective and sufficient to prevent infection, rejection and to provide stabilization.
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Directory of Open Access Journals (Sweden)
A. Fontes
1917-01-01
Full Text Available Assim em resumo pensamos que a hipersensibilidade na infeção tuberculosa é a expressão duma reação celular, autonoma e individual, consequente á agressão brusca e á destruição (dijestão incompleta dos toxicos bacilares (proteinas, globulinas e lipoides, em combinação intima ou isoladamente; a adição aos toxicos bacilares de lipoides diversos (cholesterina, lecitina, esters e principios mal definidos existentes no oleo de figado de bacalhau, atenua a sua função hipersensibilidade porque torna esses toxicos mais facilmente incorporaveis á celula sensivel por adsorpção da substancia toxica ao lipoide. Esses corpos penetram assim no interior das celulas levando comsigo ativadores dos processos enzimaticos que não so favorecem uma elaboração dijestiva mais perfeita como ainda uma melhor produção de anticorpos. O aparecimento de pequenas modalidades reacionarias no decurso duma immunisação ativa contra os antijenos saturados por lipoides mostra a necessidade dum processo de desintegração para que a função toxica se manifeste.
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Energy Technology Data Exchange (ETDEWEB)
Kundt, Miriam S [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia
2001-07-01
de preimplantacion cultivados in vitro son empleados desde hace algun tiempo para evaluar los efectos de contaminantes ambientales, en especial metales. En este trabajo se ha utilizado este modelo para presentar los efectos citotoxicos, embriotoxicos y genotoxicos del uranio. Los embriones fueron obtenidos mediante superovulacion de hembras hibridas CBA x C57 Bl, apareadas luego con machos NIH y cultivados en medio M16 como medio control. Tres experimentos diferentes se llevaron adelante 'A', 'B' y 'C' utilizando nitrato de uranilo hexahidratado UO{sub 2}(NO{sub 3}){sub 2} 6H{sub 2}O como fuente de uranio. En el experimento 'A' los embriones desde el estadio de una celula se cultivaron durante 120 hs. en la misma placa, conteniendo una concentracion final de uranio de 13, 26, 52, 104 y 208 {mu}gU/ml. En el experimento 'B' los embriones fueron puestos a cultivar desde el estadio de una celula a una concentracion final de uranio de 26, 52 y 104 {mu}gU/ml, a las 24 hs. de cultivo los embriones que pasaron a 2 celulas fueron cambiados a una placa preparada nuevamente, manteniendo las mismas concentraciones de uranio que la anterior, hasta finalizar el periodo de incubacion de 120 hs. En el experimento 'C' los embriones fueron puestos a cultivar desde el estadio de una celula a una concentracion final de uranio de 26, 52 y 104 {mu}gU/ml y fueron cambiados de placa de cultivo cada 24 hs., manteniendo estas placas nuevas las mismas concentraciones de uranio que la primera y el cultivo finalizo a las 72 hs. El clivaje embrionario desde 1 celula a 2 celulas no se ha visto estadisticamente afectado respecto del control, en los 4388 embriones analizados, en los diferentes tratamientos y las diferentes concentraciones de uranio empleadas. Desde el clivaje de 2 celulas en adelante, momento que el embrion comienza a sintetizar su propio ARNm, el retraso en el desarrollo embrionario, el grado de fragmentacion, el porcentaje de embriones atresicos y las malformaciones embrionarias
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Encinas Cerezo, María Teresa; Ros, J.M.; Gilabert Santos, Juan Antonio
2009-01-01
Dentro del marco planteado por el Espacio Europeo de Educación Superior y utilizando el entorno del Campus Virtual de la UCM, se ha creado un espacio virtual donde los estudiantes de «Farmacología, Farmacia y Terapéutica» de la Licenciatura de Veterinaria podrán consultar, organizado por secciones, material didáctico para aprender de forma activa los contenidos de esta asignatura troncal. Las herramientas presentan diversas finalidades y formatos: formativa (guiones, presentacione...
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Content and chemical composition of Hyptis marrubioides essential oil in function of seasons
Botrel, Priscila Pereira; Pinto, José Eduardo Brasil Pereira; Ferraz, Vany; Bertolucci, Suzan Kelly Vilela; Figueiredo, Felipe Campos
2010-01-01
Os oleos essenciais sao principios odoriferos armazenados em celulas especiais da planta. O oleo essencial no genero Hyptis e usado como anestesico, antiespasmodico, antiinflamatorio e pode induzir aborto em doses elevadas. O objetivo deste trabalho foi avaliar a influencia da sazonalidade no teor e composicao do oleo essencial de Hyptis marrubioides. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos (inverno, primavera, verao e outono) e seis repeticoes, totali...
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Estadística (Estadística Inferencial en Psicología) (2010/2011)
Rodrigo Giménez, María Florencia; Molina Ibáñez, Jesús Gabriel
2010-01-01
La asignatura Estadística es una asignatura troncal de carácter anual que se imparte en el 1er curso del grado en Psicología, y consta de un total de 12 créditos. La finalidad general de la asignatura es la de proveer procedimientos para dar respuesta a las cuestiones de interés para los psicólogos mediante análisis estadístico de datos, y en consecuencia tiene un carácter teórico-práctico.
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Declaration on embryonic stem cells
Casado, María; Egozcue, Josep, 1940-2006
2001-01-01
El grupo ha analizado las cuestiones referentes a la obtención y utilización de células embrionarias, llamadas células stem, células madre o células troncales, tema de extraordinaria importancia científica en el momento actual, que suscita reacciones encontradas, de gran carga ideológica, y ante el cual se requiere un debate social informado, que permita establecer el suficiente consenso para que se pueda dar lugar a la correspondiente normativa jurídica.
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Pineda-Gómez1, César-Augusto; Arenas-Mantilla, Oscar-Armando; Santos-Santos1, Nicolás
2007-01-01
Para la industria del transporte de gas natural por sistemas de tuberías, es de vital importancia garantizar la integridad del sistema con el fin de reducir costos operacionales y evitar accidentes que puedan atentar contra la seguridad física de las personas, el medio ambiente o la misma infraestructura. En este artículo se presentan los principales componentes de un estudio realizado sobre la red troncal y los ramales de distribución a algunos municipios, del Sistema Nacional de Transporte ...
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Directory of Open Access Journals (Sweden)
José Antonio Arias Navalón
Full Text Available Objetivo: Evaluar cuantitativamente los contenidos teóricos, generales y especializados, de los planes de estudios de las diplomaturas de ciencias de la salud en España. A partir de esos datos se harán algunas recomendaciones y se destacarán aspectos que podrían necesitar modificaciones. Diseño: Revisión sistemática. Emplazamiento y material de estudio: Planes de estudios de las diplomaturas de ciencias de la salud en España: Enfermería, Fisioterapia, Logopedia, Nutrición humana y dietética, Óptica y optometría, Podología y Terapia ocupacional. Mediciones: Número de horas teóricas dedicadas a materias troncales, detallando su carácter general o especializado. Resultados y conclusiones: En conjunto, los contenidos especializados y generales suponen, respectivamente, el 66,7 y el 33,3%. La mayoría de las carreras tienen más horas asignadas a materias especializadas. Los resultados oscilan entre la ausencia de materias troncales generales en las carreras de Óptica y optometría y de Logopedia y el 71,4% de carga lectiva de carácter general en la carrera de Terapia ocupacional. La carencia de conocimientos generales sobre la salud y la enfermedad puede tener consecuencias negativas en la práctica diaria y en las expectativas que tienen para hacer investigación los profesionales implicados.
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Energy Technology Data Exchange (ETDEWEB)
Zajicek, G.; Rosin, A.; Gross, J. [Department of Experimental Medicine and Cancer Research, Hebrew University, Hadassah Medical School, Jerusalem (Israel)
1962-02-15
disposent probablement pas d'une quantite suffisante de thymidine dans le liquide ascitique. Les auteurs etudient la dichotomie entre la synthese du complement entier de l'ADN et la division subsequente de la cellule. (author) [Spanish] El tritio se utiliza en Israel como indicador para estudiar una gran variedad de problemas biologicos. Los autores describen en particular los resultados de unas investigaciones en que se ha utilizado timidina tritiada para estudiar la dinamica celular en la leucemia mieloide, inducida con lines experimentales, y analizar el mecanismo de la incorporacion de esa sustancia en el acido desoxirribonucleico de celulas leucemicas y de celulas de tumores asciticos de Ehrlich. Las celulas leucemicas se marcaron in vivo inyectando en la vena yugular de ratas timidina tritiada a razon de 1 {mu}curie/g de peso corporal. Se evaluo la velocidad de aparicion de las celulas marcadas en la sangre de la periferia y en el tumor ascitico de los animales. En otros experimentos se determino la velocidad de dilucion del indicador en los nucleos, lo que permitio calcular el tiempo de duplicacion de la poblacion de mielocitos. La dinamica de las celulas transfundidas se investigo inyectando mielocitos marcados en la vena yugular de ratas normales y leucemicas. Se midio su velocidad de desaparicion de la sangre. Se examinaron varios organos para ver si contenian celulas marcadas y se observo que poco despues de la inyeccion las celulas son principalmente captadas por los pulmones, despues por el bazo y, en menor grado, por el higado. Pasadas 24 h no se pudieron detectar celulas marcadas en ningun organo. De este modo, se obtuvo informacion sobre el comportamiento de los mielocitos leucemicos en distintos organos de animales normales y leucemicos. En experimentos realizados in vitro, se anadio a una suspension celular timidina tritiada en una concentracion de 1 {mu}curie/ml. Durante la marcacion in vitro se comprobo que el numero de celulas marcadas es 40 veces mayor
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Integración de sistemas de comunicaciones móviles inalámbricas en una plataforma GIS
Casademont Serra, Jordi; López Aguilera, M. Elena; Paradells Aspas, Josep
2002-01-01
El artículo presenta una nueva plataforma desarrollada para la comercialización de servicios avanzados de información geográfica para uso en dispositivos portátiles. La plataforma utiliza las redes de telecomunicación disponibles hoy en día: Internet como red troncal y las redes celulares GSM y GPRS como redes de acceso. La plataforma implementa un sistema para la comercialización de información geográfica en forma de mapas vectoriales, que se pueden adquirir de un ser...
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Visión binocular : diagnóstico y tratamiento
Borràs García, M. Rosa
1996-01-01
Este libro está dirigido a todos los profesionales del campo de la optometría que quieran profundizar en la visión binocular. También está indicado para los alumnos de tercer curso de Optometría, tanto en asignaturas troncales como optativas. Sus contenidos están divididos en capítulos que pueden ser leídos de forma independiente, aunque es recomendable comprender el presente texto como una unidad. Su estructura abarca desde las disfunciones binoculares más frecuentes al estrabismo, la amblio...
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Giudice, Jacqueline; Godoy, Marcelo; Moyano, Estela Inés
2016-01-01
Resumen: Este trabajo presenta los resultados obtenidos a partir de la realización de entrevistas a profesores de diez materias consideradas troncales en la carrera de Psicología de una universidad argentina. Se utilizó un cuestionario-base abierto a la interacción, que los interrogó sobre las prácticas de lectura y de escritura que promueven en sus aulas. También se les solicitaron muestras del material bibliográfico y consignas de escritura o de evaluación propuestas como requisitos de apro...
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Informática (Ingeniero Técnico en Obras Públicas)
Pérez Iglesias, José Luis
2008-01-01
Como asignatura de fundamentos básicos de la informática pretende que el estudiante adquiera los conocimientos básicos necesarios para adentrarse en el aprendizaje de herramientas informáticas empleadas en las distintas disciplinas de la carrera. En particular existe una asignatura optativa en 2o curso de Programación en la cual se abordan temas como la creación de software. La asignatura Sistemas Informáticos dentro del Plan de Estudios actual es una asignatura troncal que consta de 6 Créd...
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Aprender enseñando : una propuesta de organización de la asignatura Conocimiento del Medio Natural
Directory of Open Access Journals (Sweden)
María del Carmen de Lemus Varela
2013-05-01
Full Text Available Para acercarnos al EESS es necesario adecuar los programas actuales centrándolos en el desarrollo de competencias. Aquí se presenta una posibilidad de trabajo en una asignatura troncal de las Titulaciones de Maestro de Primaria que trata de motivar al estudiante hacia el trabajo en equipo, la preparación de recursos didácticos novedosos y la reflexión ante los métodos de aprendizaje de las ciencias naturales por los universitarios a través de la lectura de textos para niños.
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Ferrús Ferré, Ramón Antonio; Díaz Romero, M. del Pilar
1999-01-01
Entre las principales directrices que actualmente determinan la evolución de las redes de telecomunicación se encuentra la adopción progresiva de tecnologías de transmisión en modo paquete. Bajo esta perspectiva, el presente trabajo describe una posible arquitectura para la integración de diferentes redes de acceso a una plataforma troncal IP y plantea el análisis de las prestaciones de los algoritmos de traspaso en función de las entidades funcionales del plano de transmisión involucradas. ...
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Créditos ECTS en la asignatura de Electrónica Analógica
Galiana-Merino, Juan José; Pascual, Carolina; Albaladejo Blázquez, Adolfo; Gimeno, Encarnación; Ortiz Zamora, Francisco Gabriel; Marini, Stephan
2007-01-01
En este trabajo se ha analizado la asignatura de electrónica analógica, asignatura troncal de Ingeniería Técnica de Telecomunicación, especialidad en Sonido e Imagen. El resultado final de este trabajo de investigación docente ha derivado en la elaboración de una guía docente adaptada al nuevo sistema de créditos ECTS, donde el proceso educativo ya no se evalúa bajo criterios de duración temporal sino por objetivos concretos, competencias y resultados.
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La toxicología en la Universidad de Sevilla
Puerto Rodríguez, María; Cameán Fernández, Ana María; Moreno Navarro, Isabel María; Pichardo Sánchez, Silvia; Prieto Ortega, Ana Isabel; Jos Gallego, Ángeles Mencía
2010-01-01
La docencia del Área de Toxicología en la Universidad de Sevilla se desarrolla en la actualidad en dos titulaciones, Farmacia y Bioquímica. En los planes de estudios actuales la carga lectiva del Área viene dada por las asignaturas de Toxicología (asignatura troncal), y Toxicología Alimentaria (asignatura optativa) en la Licenciatura de Farmacia, y de Toxicología Molecular (asignatura optativa) en la Licenciatura de Bioquímica. Una vez aprobados por la Agencia Nacional de la Evaluación de la ...
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Energy Technology Data Exchange (ETDEWEB)
Bianchi, P. A.; Crathorn, A. R.; Shooter, K. V. [Chester Beatty Research Institute, Institute of Cancer Research, London (United Kingdom)
1962-02-15
balayage continu. Les deux methodes de mesure ont donne des resultats sensiblement differents. Pour chaque cellule, l'activite due au tritium, calculee d'apres les autoradiographies, a toujours paru superieure a celle de l'ADN isole. En mesurant ensuite a l'aide du compteur a balayage continu l'activite de cellules entieres, apres lavage et homogeneisation, on a obtenu des chiffres qui concordaient avec les resultats de l'autoradiographie. Il semble donc, en l'occurrence, que l'autoradiographie ne permette pas de mesurer de maniere satisfaisante la synthese de l'ADN. On a etudie l'activite associee, autre que celle de l'ADN, et entrepris sur d'autres types de cellules des etudes analogues de l'activite totale due au tritium et de l'activite de l'ADN isole; des effets similaires ont ete observes. A partir de ces donnees, on a pu distinguer plusieurs phases dans le processus de synthese : 1 Degree-Sign incorporation initiale de la thymidine a la cellule; 2 Degree-Sign phosphorylation en deux etapes au moins; 3 Degree-Sign formation d'ADN par polymerisation de la thymidine phosphorylee. Ainsi, on simplifierait a l'exces en supposant que l'incorporation de thymidine a la cellule permette de mesurer la synthese de l'ADN; il semble cependant qu'en utilisant cet indicateur on puisse obtenir des indications utiles sur les etapes preliminaires du processus. (author) [Spanish] En el curso de estudios sobre la biosintesis del acido desoxirribonucleico se han realizado algunos experimentos, utilizando celulas asciticas de Ehrlich, para investigar la fijacion e incorporacion de timidina-{sup 3}H. Despues de incubar in vitro las celulas marcadas con este compuesto, se han tomado autorradiografias de las mismas; tambien se ha aislado el acido desoxirribonucleico y se ha medido la actividad del {sup 3}H utilizando un contador de flujo. Al comparar los dos metodos de medicion, se advierte una marcada discrepancia; la actividad del {sup 3}H por celula, calculada a base de las
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Santamaría, J.; Espinilla, M.; Rivera, A. J.; Romero, S.
2010-01-01
Arquitectura de Computadores es una asignatura troncal de segundo ciclo de la titulación de Ingeniería de Telecomunicación (P.E. 2004) de la Universidad de Jaén, que desde el curso académico 2009/10 cuenta con una metodología de aprendizaje proactivo para motivar al alumno en la realización de las prácticas. En concreto, se ha abordado la enseñanza de la materia de paralelización de algoritmos haciendo uso de GPUs de tarjetas gráficas convencionales. Además, se ha d...
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Cálculo avanzado para ingeniería : teoría, problemas resueltos y aplicaciones
Arias Vicente, Irene
2008-01-01
Este libro sigue el esquema básico de la asignatura troncal Matemáticas 2 (capítulos 1, 2, 3, 4 y 5) y parte del temario de las asignaturas Matemáticas 1 (capítulo 1) y Matemáticas 3 (capítulos 6 y 7), que los autores imparten en la EUETIB. No obstante, su contenido es perfectamente adaptable a cursos de álgebra lineal, cálculo en varias variables y ecuaciones diferenciales de cualquier ingeniería. El texto tiene como objetivo principal iniciar al estudiante en los conceptos básicos del álgeb...
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Del Castillo Díez, María
2015-01-01
El ser humano ha buscado siempre una solución contra el sufrimiento. A pesar de formar parte intrínseca de su vida, sigue sin aceptar el dolor, la enfermedad ni tampoco la muerte.En los últimos años la medicina y la biología se han unido en una lucha sin cuartel contra las enfermedades y la muerte, desarrollando una serie de técnicas e investigaciones (la clonación, las investigaciones biomédicas con células troncales o las terapias celulares y génicas) que han marcado un hito en el desarroll...
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Las células madre y sus aplicaciones actuales
Reguero Mera, Marta
2017-01-01
Introducción: Se conocen diferentes tipos de células, pero todas ellas tienen una característica en común, que provienen de las células madre. Las células madre, también denominadas células troncales o progenitoras, poseen varias características que las diferencian del resto de células. Existen varias clasificaciones para estas células: dependiendo de su potencial, capacidad de diferenciación o por su origen. El uso de dichas células, o derivadas de éstas, para reparar o renovar tejidos o cél...
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Propuesta de integración de soluciones empresariales VoIP con software libre
Barba Vera, Ruth Genoveva
2012-01-01
Se estudió voip en cisco y elastix para integrarlas y compartir servicios, a través de la troncal sip. Con método experimental, en ambiente de pruebas con tres escenarios, se instaló y configuró Cme 3.3 en router 2811 y elastix 2.2 en pc. Se realizaron llamadas a lo interno de las centrales telefónicas Call Manager Express ó Elastix comprobando la interoperabilidad de las mismas demostrándose que existe una comunicación full dúplex entre tecnologías. Se utilizó equipos cisco: un router 2811,...
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Llitjós Viza, Anna
2011-01-01
Aquest projecte de dos anys de durada, ha tingut com a objectius: el disseny i la creació de recursos multimèdia, així com, l’optimització de metodologies d'aplicació de sistemes telemàtics interactius per a la millora de la docència universitària. Com a entorn telemàtic s’ha utilitzat la plataforma de treball cooperatiu BSCW (Basic Support for Cooperative Work). S'ha dissenyat i produït un recurs multimèdia enfocat a l'alumnat de l'assignatura troncal Ciències naturals i la se...
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Medina Redondo, María de
2008-01-01
La formación de la pared celular de Schizosaccharomyces pombe requiere la actividad coordinada de enzimas involucradas en la biosíntesis y modificación de sus componentes, entre los que destacan por su abundancia los glucanos. El complejo enzimático ?-glucán-sintasa sintetiza ?-1,3-glucanos lineales, que permanecen desorganizados y solubles en álcali hasta que se establecen enlaces covalentes entre los ?-1,3-glucanos y otros componentes de la pared celular. Las transferasas de la pared celula...
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Diseño de placas solares e implementación de un transmisor experimental AX.25 para el 3Cat-1
Gonzalvez Foguet, Ricard
2016-01-01
Explains the design and construction of two types of solar panels for the 3cat1, one type based on commercial high efficiency multi-junction solar cells and other based in UPC Electronic Engineering Department in-house developed solar cells. Also describes the design and implementation of a microcontroller based experimental transmitter to send data packets to the 3cat1 ground station. Diseño y construcción de dos tipos de paneles solares para el 3cat1, el primero basado en celulas solares...
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Ada in Introductory Computer Science Courses
1993-01-01
M2 111418111 1111111 I s%1 tems to des elop soaftware Systems for IM5. ONhalt oIf dt ufl’wae mownev b f "bs" arn .exti to k ,ulift la Ada. COMPUT...beftjobamdsodeckldthesespienicngamnug them. A celula 101110011ui systm Service in Ada& using an rmniticdawau dipay shows *I tatus. The systm objweaniiimd...liftt aftr of Fucal Nikkao Wirh. Some say Software i - , I, ced a pse-validaed ver. origina soitweim is coded. The idWa is to that Ads is the las gpat
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Impacto ambiental de un nuevo modelo de sistema de transporte público para Caracas
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Josefina Mundu00F3 Tejada
2011-01-01
Full Text Available En el ámbito urbano una de las principales fuentes contaminantes del ambiente son los vehículos automotores. Una estrategia para reducir el número de los vehículos en circulación y frenar el deterioro ambiental es el mejoramiento del sistema de transporte público y estimular su uso. Para hacer atractivo el empleo del transporte público en Caracas es indispensable hacer cambios importantes en este. Se propone la implantación de un sistema de Bus Rapid Transit (BRT que responda a los deseos de movilización de la población expresados en la Encuesta de Movilidad de 2005. En dicha propuesta, las líneas de la red de transporte masivo existente constituirían rutas troncales del sistema más importantes; el BRT contemplaría la operación de estas rutas a lo largo del eje este-oeste de la ciudad y de los principales corredores viales de los valles secundarios localizados al suroeste y sureste de Caracas; y las rutas alimentadoras operarían desde distintos sectores hacia las rutas troncales. La estimación del impacto ambiental derivado de la implantación del sistema propuesto, calculado solo con base en la sustitución de unidades minibús por autobuses en los principales corredores, señala ahorros sustanciales en consumo de espacio y de combustible; una disminución moderada del ruido; y reducciones de las emisiones de monóxido de carbono (CO, óxidos de nitrógeno (NOx e hidrocarburos (HC.
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Pronunciamiento de la Academia Nacional de Medicina sobre ‘Clonación Humana’
Perales Cabrera, Alberto
2013-01-01
Las cuestiones en debate: 1° ¿Cuándo comienza la vida humana? 2° ¿Es lícito crear embriones por clonación para implantarlos y crear nuevos seres humanos? ¿Puede considerarse la clonación como una forma alternativa de reproducción asistida? 3° ¿Es lícito crear embriones para destruirlos— y cultivar sus células con el propósito de curar enfermedades? 4° ¿Qué alternativas existen para la obtención de células troncales para terapia, sin usar clonación? 5° ¿Constituyen un problema único o problema...
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Cinemática y estática : teoría y problemas
Martín García, José
1997-01-01
La presente obra se plantea como una introducción a las leyes fundamentales de la mecánica y sus aplicaciones a los problemas técnicos. La cinemática estudia el movimiento de los cuerpos y sólo requiere para su descripción las magnitudes físicas masa y fuerza, cuyo desarrollo se basa en las leyes de Newton. El texto está dirigido a los alumnos de primer año de universidad de las carreras técnicas en las que la física básica es una asignatura troncal. El contenido teórico se complementa con un...
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Broerse, J. J.; Barendsen, G. W. [Radiobiological Institute of the Organization for Health Research TNO, Rijswijk (Z.H.) (Netherlands)
1964-03-15
avait lieu dans des bottes de culture a fond mince en Melinex et dans de petits tubes flexibles en nylon et en caoutchouc au silicium. Les auteurs ont determine les flux de neutrons en mesurant l'activation de pastilles de soufre placees, selon les cas, entre les boftes ou entre les tubes. Ils examinent les divers problemes que pose le calcul de la dose d' apres le flux de neutrons. Comme il n'y a pas equilibre du rayonnement autour des cellules, ils analysent les inexactitudes qui en resultent dans les determinations de la dose. Le memoire donne les courbes dose-survie pour les neutrons des deux types. Pour les neutrons de 3 MeV, on a trouve une EBR allant de 6, 5 dans le cas de faibles doses a 3,1 dans le cas de doses elevees; pour les neutrons de 15 MeV, l 'EBR variait de 1,9 a 1,6. En comparant ces valeurs de l'EBR avec le rapport EBR-TLE obtenu au cours d'experiences precedentes avec des deuterons et des particules alpha, on peut calculer le TLE effectif pour les neutrons utilises. Pour resoudre certains problemes relatifs a la mort des animaux d'experience apres exposition aux rayons X ou aux neutrons, les auteurs ont mis au point une technique permettant d'utiliser les cellules contenues dans de petits tubes pour mesurer la dose effective (c'est-a-dire la dose corrigee en fonction de l'EBR) en des points interessants dans des fantomes ou des animaux. (author) [Spanish] Los autores presentan relaciones entre dosis y efecto comprobadas en el estudio de la inhibicion de la formacion de clonos en cultivos de tejido renal humano despues de la irradiacion con neutrones monoenergeticos de unos 3 MeV y unos 15 MeV, respectivamente. Para los neutrones de 3 MeV, la intensidad de dosis fue de 0,2 rad/min, mientras que para los neutrones de 15 MeV, se alcanzaron intensidades de dosis de 2,7 rad/min y 12 rad/min. Las celulas se irradiaron en capsulas de cultivo con fondo delgado de Melinex y en tubos finos flexibles de nylon y de caucho de silicona. Los flujos neutronicos se
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Gestão organizacional sob a lógica da competência: aplicação na pequena empresa.
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Mariana Musetti Munck
2008-02-01
Full Text Available Este estudo, sustentado nas premissas teoricas do modelo de gestão por competencias, objetiva explorar, descrever e mudar a sistematica de execução das atividades de uma pequena empresa de consultoria. Orientando-se por autores que propoem a operacionalização do conceito de competencias nas organizacões, construiram-se quadros de referencias para as celulas da organização de modo que houvesse mais transparencia e consistencia nas ações de gestão, e isso representa um grave problema das pequenas empresas. Os quadros são compostos de atributos como missão, atribuições, contribuições, indicadores de resultados e competencias, todos definidos com base nas estrategias e nos objetivos almejados pela organização. Ante a proposta de não apenas explorar e descrever, mas tambem de mudar, o estudo utilizou como orientação metodologica a pesquisa-ação. Esse metodo não se limita apenas a descrever uma situação, mas tambem pretende desencadear, em certos casos, mudancas no seio da coletividade envolvida. O proprio processo de busca e os resultados alcancados demonstraram, a principio, que a estruturação de uma empresa por competencias gera turbulencias iniciais, principalmente pela radicalidade da mudança (neste caso e pelas particularidades do conceito. A nova estrutura tem provocado mudanças culturais, sobretudo na açao dos gestores que tem agora informações claras sobre as atribuições e exigencias cabiveis a cada celula, bem como de seus respectivos indicadores de desempenho.
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Tamara Muñoz Nieto
2010-06-01
Full Text Available En esta investigación se recoge un análisis sobre la forma de organizar la asignatura de organización del centro escolar en diferentes universidades de la Comunidad de Madrid. La asignatura de organización del centro escolar es una asignatura de carácter troncal y se imparte en los estudios de magisterio. Para un alumno universitario, en el caso de las universidades públicas, su centro de estudio depende de una nota. Por lo tanto se puede preguntar cómo hubiera sido su formación en otra universidad. Con esta investigación se trata de comparar los objetivos, metodología y forma de evaluar así como los materiales utilizados.
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Gisone, P; Dubner, D; Michelin, S; Perez, M R [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Barboza, M [Hospital de Clinicas Jose de San Martin, Buenos Aires (Argentina)
1998-07-01
produccion de apoptosis en un modelo experimental de irradiacion prenatal. Se irradiaron cultivos primarios de cerebro (rata Wistar, dia 15 de e.g.), en un rango de dosis hasta 2 Gy (Cobalto 60). Se evaluo la respuesta a la incubacion con distintos neuroprotectores. Se estudiaron los siguientes parametros: alteraciones de la morfologia celular, fragmentacion de cromatina y fraccion de celulas apoptoticas. Las celulas irradiadas mostraron condensacion nuclear con presencia de cuerpos apoptoticos. Las corridas electroforeticas evidenciaron un patron de fragmentacion caracteristico ('laddering') con aumento dosis-dependiente en la fraccion de celulas apoptoticas analizadas por citometria de flujo. La incubacion con neuroprotectores no indujo cambios significativos en las concentraciones y los tiempos ensayados. Se analizan los resultados obtenidos. Se discute acerca del rol de la apoptosis, su relacion con la injuria oxidativa y los fenomenos de excitotoxicidad como mecanismo de danio radioinducido en el sistema nervioso central en desarrollo. (autor)
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Aspectos éticos sobre la investigación y tratamiento con células troncales
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Koldo Martínez
2008-01-01
Full Text Available La popularización de la existencia de las células madre y sus posibles usos en la medicina regenerativa han despertado un vivo interés en la población y unas expectativas desaforadas de curación de todas o casi todas las enfermedades. Sin embargo, la utilización de estas células merece distintas valoraciones éticas según cuál sea su procedencia y métodos de obtención. Las procedentes de adulto y de cordón umbilical no presentan problemas éticos distintos a cualquier otro tipo de investigación y/o tratamiento. Son las procedentes de embriones las que generan problemas específicos y en el texto se defiende la moralidad de su uso siempre que se respeten unos límites mínimos.
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Aspectos éticos sobre la investigación y tratamiento con células troncales
Koldo Martínez
2008-01-01
La popularización de la existencia de las células madre y sus posibles usos en la medicina regenerativa han despertado un vivo interés en la población y unas expectativas desaforadas de curación de todas o casi todas las enfermedades. Sin embargo, la utilización de estas células merece distintas valoraciones éticas según cuál sea su procedencia y métodos de obtención. Las procedentes de adulto y de cordón umbilical no presentan problemas éticos distintos a cualquier otro tipo de investigación...
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Stem Cells and Cancer; Celulas madre y cancer
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Segrelles, C.; Paraminio, J. M.; Lorz, C.
2014-04-01
Stem cell research has thrived over the last years due to their therapeutic and regenerative potential. Scientific breakthroughs in the field are immediately translated from the scientific journals to the mass media, which is not surprising as the characterisation of the molecular mechanisms that regulate the biology of stem cells is crucial for the treatment of degenerative and cardiovascular diseases, as well as cancer. In the Molecular Oncology Unit at Ciemat we work to unravel the role of cancer stem cells in tumour development, and to find new antitumor therapies. (Author)
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Silva, Fernando; Carzoglio, Eduardo; Hryciuk, Pedro [TGN - Transportadora de Gas del Norte S.A. (Argentina). Depto. de Integridad
2003-07-01
TGN had a rupture in service on Gasoducto Troncal Norte. After initial evaluation of the causes of the rupture it was concluded that it had been caused by Stress Corrosion Cracking (SCC). Subsequent investigation in the area of the rupture revealed that colonies of cracks, typical of SCC were found in pipes located near the rupture. In order to put back in service the pipeline in a safety condition, SCC mitigation activities were performed. A decision was made to conduct a hydro test along approximately 30 kilometers of pipe. The stages of the works, the problems faced and the solutions found are dealt with, as well as the conclusions reached upon completion of the works which allowed a better understanding of SCC phenomenon. The methodology for the identification of those areas susceptible to SCC is also described. (author)
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La inteligencia de negocios: una estrategia para la gestión de las empresas productivas
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Cordero-Guzmán, Diego
2017-08-01
Full Text Available The paper aims to determine a set of indicators about the performance of productive enterprises in Canton La Troncal, province of Cañar, Ecuador, to use “Business Intelligence” (Business Intelligence BI as the best practice that supports organizational management and achievement of the strategic objectives. For this purpose, information was first collected through a survey that was carried out in local companies, based on a specific sample, with questionnaires and interviews. Then, based on the information obtained, a Balanced Scorecard was designed with the most significant key performance indicators for the companies in the sample, so that they can be implemented with the multidimensional services offered by business intelligence tools. Finally, the reports were presented in control panels, with a fine granularity range, which allow managers to make clear decisions, reducing the degree of uncertainty.
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Introducción a la Matemática económico-empresarial. Una experiencia en la Universidad de Valencia.
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Liern Carrión, Vicente
1998-01-01
Full Text Available En este trabajo analizamos los resultados de la creación de un módulo de libre elección denominado “Introducción a la Matemática Económico-Empresarial” en la Universitat de València. Con él se pretende reducir las diferencias existentes en los conocimientos previos de matemáticas de los estudiantes que acceden por primera vez a las licenciaturas de Economía, de Administración y Dirección de Empresas y a la diplomatura de Ciencias Empresariales. Analizamos la influencia de este módulo sobre el resto de modulos troncales de matemáticas de las titulaciones a las que afecta y, aunque sólo disponemos de los datos de la única convocatoria realizada, ya es posible deducir algunos indicios sobre su efectividad.
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Energy Technology Data Exchange (ETDEWEB)
Garcia Hernandez, Carlos Felipe; Ibarguengoytia Gonzalez, Pablo Hector; Flores Garcia, Andres; Franco Campos, Laura Elena [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2011-06-13
This verification procedure is based on a research work on the possible risks to human health by exposure to the radiation of electromagnetic waves produced by the radio communications, cases of study: cellular telephony, radio digital troncalized and wireless telephony IP of Voice on IP (wireless local area network). The revision of all the international standards and the applicable national standardization was included, as well as the verification of fulfillment. [Spanish] Este procedimiento de verificacion esta basado en un trabajo de investigacion sobre posibles riesgos a la salud humana por exposicion a la radiacion de ondas electromagneticas producidas por la radiocomunicaciones, casos de estudio: telefonia celular, radio troncalizado digital y telefonia IP inalambrica de Voz sobre IP (red de area local inalambrica). Se incluyo la revision de todos los estandares internacionales y de la normatividad nacional aplicable, asi como la verificacion de cumplimiento.
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Sordi, Alexandre; Lobkov, Dmitri D.; Lopes, Daniel Gabriel; Rodrigues, Jean Robert Pereira [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Mecanica], e-mail: asordi@fem.unicamp.br, e-mail: lobkov@fem.unicamp.br, e-mail: danielg@fem.unicamp.br, e-mail: jrobert@fem.unicamp.br; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin], e-mail: Lh2ennio@ifi.unicamp.br
2006-07-01
The objective of this paper is to present the operation flow diagram of an electricity generation system based on the biomass integrated gasification fuel cell of the type PEMFC (Proton Exchange Membrane Fuel Cell). The integration between the gasification and a fuel cell of this type consists of the gas methane (CH4) reforming contained in the synthesis gas, the conversion of the carbon monoxide (CO), and the cleaning of the gaseous flow through a PSA (Pressure Swing Adsorption) system. A preliminary analysis was carried out to estimate the efficiency of the system with and without methane gas reforming. The performance was also analyzed for different gasification gas compositions, for larger molar fractions of hydrogen and methane. The system electrical efficiency was 29% respective to the lower heating value of the gasification gas. The larger the molar fraction of hydrogen at the shift reactor exit, the better the PSA exergetic performance. Comparative analysis with small gas turbines exhibited the superiority of the PEMFC system. (author)
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Selma Candelária Genari
2010-10-01
Full Text Available Many chemotherapeutic agents with a potential against solid tumors or leukemia can cause lymphopenia. Tamoxifen (TAM is a synthetic non-steroidal anti-estrogen drug employed in female breast cancer treatment. The present study investigated the capacity of TAM to induce cell death in human lymphocytes cultivated in vitro. Lymphocytes were obtained from young (25-30 years; n = 3 and elderly women (58-77 years; n = 3 and cultivated for 24 or 48h, with or without TAM (20 ƒÊM. After the culture, cell viability, immunocytochemical response and ultrastructure were evaluated. TAM affected lymphocytes in a time- dependent manner, and cells obtained from elderly women were the most sensitive to TAM. Immunocytochemicalanalysis evidenced higher frequency of apoptosis in treated cells, and the ultrastructural study revealed autophagic vacuoles, differing from the controls. In summary, the treated lymphocytes were affected by TAM, leading to cell death by apoptosis and autophagy.Muitos agentes quimioterapicos com potencial contra tumores solidos ou leucemias podem causar linfopenia. O Tamoxifeno (TAM e um agente antiestrogeno nao-esteroidal empregado no tratamento de cancer de mama feminino. O presente trabalho investigou a capacidade do TAM em induzir morte celular em linfocitos humanos cultivados in vitro. Oslinfocitos foram obtidos de mulheres jovens (25-30 anos; n = 3 e idosas (58-77 anos; n = 3 e cultivados por 24 ou 48h, com ou sem TAM (20 ƒÊM. Apos a cultura, foram analisadas a viabilidade celular, a resposta imunocitoquimica e a ultraestrutura. Os resultados indicam que o Tamoxifeno induziu morte celular em linfocitos de ambos os grupos, entretanto, as celulas das mulheres idosas apresentaram-se mais sensiveis ao tratamento. A analise imunocitoquimica mostrou maior frequencia de apoptose nas celulas tratadas e o estudo ultraestrutural revelou vacuolos autofagicos nos linfocitos expostos ao Tamoxifeno. Em conclusao, nosso estudo revelou que o TAM
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Jerson Reyes S
2009-08-01
Full Text Available En este trabajo se presenta una metodología para minimizar la frecuencia de fallas en Sistemas de Distribución radiales considerando una carga uniformemente distribuida. Se utiliza una aproximación lineal para la ubicación de reconectadores. Este trabajo basa su estudio en la minimización del índice de Frecuencia Media de Interrupción por Potencia instalada, el cual es utilizado como parámetro de regulación y clasificación de las compañías distribuidoras chilenas, según la reglamentación eléctrica vigente. Se introduce además el concepto de Factor de Distancia entre línea Troncal y arranque, el cual puede ser utilizado como herramienta de discriminación para acotar el número de reconectadores a instalar en la línea troncal. Además permite discriminar en base a la data histórica de la línea, si un arranque cualquiera, debe ser evaluado económicamente, como un nuevo alimentador, de forma tal que el índice Frecuencia Media de Interrupción por Potencia instalada sea minimizado.This paper presents a framework for minimizing the average interruption frequency in radial Distribution Systems with uniformly distributed loads. Here, the position of the reclosers has been modeled using a linear approximation. The objective of this paper is to minimize the average interruption frequency per installed power. According to the current electric regulation in Chile, this index is the metric used to regulate and classify the performance of utilities. In the analysis a novel concept of Distance Factor between the main feeder and a branch feeder was introduced. This concept can be utilized as a theoretical limit for the number of switches to install on the main feeder. In addition, based upon the service history of the line, the distance factor determines if a certain line must be economically assessed like a new feeder so that the aforementioned performance index of average interruption frequency per installed power is minimized.
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AGUSTÍN SCANFERLA
2015-01-01
Full Text Available RESUMENSe describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior, procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al géneroCeratophrys, restos de caparazón de tortugas terrestres del géneroChelonoidis, vértebras asignables al lagarto de la familia TeiidaeTupinambis, y una vértebra troncal de serpiente comparable al género de colubroideos actualesPhilodryas. Tanto los registros terciarios previos de géneros actuales de anfibios y reptiles en América del Sur, como así también la asociación recuperada en el Mioceno Superior de La Pampa sugieren que la mayoría de los géneros que componen la herpetofauna Neotropical estaban presentes en el Mioceno, patrón similar al observado en otras regiones del mundo.
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Bernabé Escobar Pérez
2004-01-01
Full Text Available Los estudios de turismo se incorporaron a la Universidad en 1996, con la aprobación de las Directrices Generales de la Diplomatura en Turismo. Al incluirse en las mismas a la Contabilidad como materia troncal, nos hemos planteado mostrar en este trabajo empírico la situación real de esta disciplina en los distintos Planes de Estudio en vigor. Como conclusión general del estudio destacamos la imposibilidad de conseguir el objetivo enunciado relativo a la formación de gestores, al menos en lo que a la Contabilidad se refiere, dado su escaso peso en los Planes de Estudio. Especialmente deplorable resulta la situación de la Contabilidad de Gestión, con una escasísima presencia. Esta conclusión nos ha hecho reflexionar acerca de la importancia, a veces no suficientemente considerada, de los procesos de elaboración y reforma de Planes de Estudio.
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Francisco Javier Otero-Mendoza
2017-06-01
Full Text Available Niño de 1 año 10 meses de edad, originario de Irapuato, Guanajuato, sin antecedentes de importancia para el padecimiento actual. Inició dos meses previos a su ingreso con crisis convulsivas tónico-clónicas generalizadas de 15 segundos de duración durante el sueño. Se realizó electroencefalograma que reportó actividad epileptiforme, por lo que se dio tratamiento con ácido valproico. Una semana previa al ingreso se agregó ataxia troncal impidiendo la marcha, por lo que se realizó una tomografía axial computarizada de cráneo en la que se observó un tumor en fosa posterior con densidad heterogénea y áreas de necrosis central que obliteraba el cuarto ventrículo, ocasionando efecto de masa y desplazamiento ventral del tallo cerebral. Por tal motivo, fue referido a nuestra institución.
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Directory of Open Access Journals (Sweden)
M.ª del Carmen Jiménez Díaz
Full Text Available El envejecimiento poblacional ha condicionado que la mayor parte de la actividad profesional de numerosos titulados de diferentes carreras se realice en personas ancianas. En su vertiente no intencional, el abandono del anciano como tipo de maltrato se puede deber a un conocimiento inadecuado (tal y como se define la impericia profesional. Por ello, la etapa de formación de la carrera reviste gran importancia en el cumplimiento de la misión universitaria. Así, todos los profesionales que desarrollen su actividad profesional con mayores deben tener conocimientos en gerontología que les permitan obtener, en cada momento, los mejores resultados posibles. Metodología: análisis descriptivo de los planes de estudio de las carreras de Enfermería, Medicina, Fisioterapia, Trabajo Social, Terapia Ocupacional y Ciencias de la Actividad Física y el Deporte. Conclusiones: excepto en Enfermería y Terapia Ocupacional, el resto de titulaciones universitarias no ofertan asignaturas troncales relacionadas con el envejecimiento.
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Directory of Open Access Journals (Sweden)
Bernabé Escobar Pérez
2004-01-01
Full Text Available Los estudios de turismo se incorporaron a la Universidad en 1996, con la aprobación de las Directrices Generales de la Diplomatura en Turismo. Al incluirse en las mismas a la Contabilidad como materia troncal, nos hemos planteado mostrar en este trabajo empírico la situación real de esta disciplina en los distintos Planes de Estudio en vigor. Como conclusión general del estudio destacamos la imposibilidad de conseguir el objetivo enunciado relativo a la formación de gestores, al menos en lo que a la Contabilidad se refiere, dado su escaso peso en los Planes de Estudio. Especialmente deplorable resulta la situación de la Contabilidad de Gestión, con una escasísima presencia. Esta conclusión nos ha hecho reflexionar acerca de la importancia, a veces no suficientemente considerada, de los procesos de elaboración y reforma de Planes de Estudio.
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Energy Technology Data Exchange (ETDEWEB)
Marrian, D. H.; Marshall, Barbara; Mitchell, J. S.; Simon-Reuss, I. [Department of Radiotherapeutics, University of Cambridge, Cambridge (United Kingdom)
1962-02-15
tetrasodica del acido 2-metil-l,4-naftoquinon-difosforico (''Synkavit'' Roche), asi como algunos de los metodos que se han empleado para marcar este y otros compuestos analogos. Sintetizaron el compuesto tritiado en forma de obtener una substancia radioquimicamente pura de 28 c/mmol (1 atomo de tritio por molecula) de actividad especifica. Demuestran que este producto penetra muy rapidamente en las celulas vivas, tanto in vivo como in vitro y que, en igualdad de condiciones los cultivos de celulas malignas incorporan en grado mucho mayor el compuesto marcado que los cultivos de celulas normales. Describen las investigaciones preliminares del empleo clinico de ese producto en casos avanzados de tumores malignos que suelen ser refractarios a otros tratamientos, observandose que la medula osea absorbe menor cantidad del compuesto que el tumor (en algunas ocasiones, hasta cinco veces menos). (author) [Russian] Dejstvie tetrasoda - 2-metil-1: 4- naftagidrohinondifosfata (Sinkavit - proizvodstvo Roshe) v kachestve radio- senitajzera obsuzhdaetsja narjadu s bolee rannimi metodami mechenija jetih i podob- nyh molekul. Sintez jetogo soedinenija, mechennogo tritiem, byl sdelan dlja togo, chtoby polu- chit' radiohimicheskoe chistoe lekarstvo s udel'noj aktivnost'ju v 28 kjuri/mil- limol' (odin atom tritija na molekulu). Budet pokazano, chto jeto soedinenie bystro vhodit v zhivuju kletku kak v este- stvennyh, tak i i laboratornyh uslovijah i chto kul'tury zlokachestvennyh kletok pogloshhajut mechenye atomy v gorazdo bol'shem ob{sup e}me, chem kul'tury normal'nyh kletok pri teh zhe uslovijah. Budut opisany predvaritel'nye issledovanija primenenija jetogo lekarstva na pacientah, imejushhih zlokachestvennye opuholi i nahodjashhihsja v tjazhelom ili neizlechimom sostojanii; usvoenie kostnym na kojefficient 5 mozgom nizhe, chem usvoenie opuhol'ju. (author)
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Magnetic nanoparticles for cancer therapy; Nanoparticulas magneticas para o tratamento do cancer
Energy Technology Data Exchange (ETDEWEB)
Bakuzis, Andris F. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Instituto de Fisica
2014-07-01
Full text: Magnetic nanoparticles have been used in several biomedical applications, spanning from cell separation, early diagnosis of metastasis to even the treatment of cancer via magnetic hyperthermia (MH). This last technique consists in the increase of temperature of nanoparticles when their magnetic moments interact with a magnetic alternating field. This effect has been suggested as an innovative therapy to cancer treatment, due to the delivery of heat or therapeutic agents, such as drugs, genes, and others. In addition, several clinical studies has demonstrated synergetic effects between hyperthermia and radiotherapy [1]. This indicates a great therapeutic potential for this noninvasive and targeted technique. In this talk we will discuss results from the literature and from our own group in the treatment of cancer via magnetic hyperthermia. Several types of magnetic nanoparticles suggested for this application will be discussed, as well as the historical evolution of this procedure, which although suggested in the late 50' only recently was approved in Europe for treatment of humans with brain tumors. (author) [Portuguese] Full text: Nanoparticulas magneticas tem sido utilizadas em diversas aplicacoes biomedicas, desde a separacao de celulas, marcacao de celulas-tronco, diagnostico precoce de metastases ao tratamento do cancer via hipertermia magnetica (HM). Esta ultima tecnica consiste no aumento da temperatura de nanoparticulas quando seus momentos magneticos interagem de forma adequada com um campo magnetico alternado. Este efeito tem sido idealizado como uma nova terapia para o tratamento do cancro, seja via entrega seletiva de calor ou mesmo pela liberacao de farmacos, genes ou outros agentes terapeuticos por meio desta acao externa. Adicionalmente, diversos estudos clinicos tem demonstrado efeitos sinergicos entre a hipertermia e tecnicas tradicionais de tratamento oncologico, como quimioterapia e radioterapia. Isto indica um forte potencial
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Oncogenes, radiation and cancer; Oncogenes, radiacion y cancer
Energy Technology Data Exchange (ETDEWEB)
Michelin, S C
1999-12-31
The discovery of the oncogenic virus and the analysis of its nucleic acid, together with the development of new biochemical technology have permitted the partial knowledge of the molecular mechanisms responsible for the cellular neoplastic transformation. This work, besides describing the discovery of the first oncogenic virus and the experiments to demonstrate the existence of the oncogenes, summarizes its activation mechanisms and its intervention in cellular metabolisms. Ionizing radiation is among the external agents that induce the neoplastic process. Its participation in the genesis of this process and the contribution of oncogenes to the cellular radioresistance are among the topics, which are referred to another topic that makes reference. At the same time as the advancement of theoretical knowledge, lines of investigation for the application of the new concepts in diagnosis, prognosis and therapeutical treatment, were developed. An example of this, is the study of the participation of the oncogen c-erbB-2 in human breast cancer and its implications on the anti tumoral therapy. (author) 87 refs., 7 figs., 3 tabs. [Espanol] El descubrimiento de los virus oncogenicos y el analisis de su acido nucleico, junto con el desarrollo de nuevas tecnicas bioquimicas, ha permitido conocer parcialmente los mecanismos moleculares responsables de la transformacion de una celula normal en neoplasica. En este trabajo, ademas de describir el descubrimiento de los primeros virus oncogenicos y las experiencias para demostrar la existencia de los oncogenes, se resumen sus mecanismos de activacion y su intervencion en el metabolismo celular. Entre los agentes expernos que inducen un proceso oncogenico, se encuentran las radiaciones ionizantes. Su participacion en la genesis de este proceso y la contribucion de los oncogenes a la radioresistencia de las celulas tumorales, es otro de los temas a que se hace referencia. Paralelamente al avance del conocimiento teorico, se
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Directory of Open Access Journals (Sweden)
José Antonio Arias Navalón
2003-12-01
Full Text Available Objetivo: Evaluar cuantitativamente los contenidos teóricos, generales y especializados, de los planes de estudios de las diplomaturas de ciencias de la salud en España. A partir de esos datos se harán algunas recomendaciones y se destacarán aspectos que podrían necesitar modificaciones. Diseño: Revisión sistemática. Emplazamiento y material de estudio: Planes de estudios de las diplomaturas de ciencias de la salud en España: Enfermería, Fisioterapia, Logopedia, Nutrición humana y dietética, Óptica y optometría, Podología y Terapia ocupacional. Mediciones: Número de horas teóricas dedicadas a materias troncales, detallando su carácter general o especializado. Resultados y conclusiones: En conjunto, los contenidos especializados y generales suponen, respectivamente, el 66,7 y el 33,3%. La mayoría de las carreras tienen más horas asignadas a materias especializadas. Los resultados oscilan entre la ausencia de materias troncales generales en las carreras de Óptica y optometría y de Logopedia y el 71,4% de carga lectiva de carácter general en la carrera de Terapia ocupacional. La carencia de conocimientos generales sobre la salud y la enfermedad puede tener consecuencias negativas en la práctica diaria y en las expectativas que tienen para hacer investigación los profesionales implicados.Objective: To assess general and specialized theoretic contents of core curricula of health professions in Spain, in order to make some recommendations to improve these curricula and to highlight some areas needing further modifications. Design: Systematic revision. Setting and study selection: Core curricula of health professions in Spain: Nursing, Physical therapy, Speech-language pathology, Nutrition and dietetics, Optometry, Podiatry and Occupational therapy. Measurements: Number of theoretic hours devoted to both general and specialized subjects. Results and conclusions: Overall, specialized and general contents are 66.7% and 33
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Neuropatía Endémica Crónica Asociada con Virus Humano Linfotrófico
Directory of Open Access Journals (Sweden)
Jaime G. Gómez
1990-04-01
Full Text Available
Diagnóstico y Tratamiento de la Neuropatía Endémica Crónica Asociada con Virus Humano Linfotrófico de Células T, Tipo I (HTLV-l
El propósito del presente artículo es haccr una breve revisión del estado actual de la Neuropatía endémica crónica asociada con el Virus Humano Linfotrópico de Celulas T-tipo L conocido por la sigla inglesa HTLV-I y presentar el primer caso tratado con éxito. logrando posiblemente la curación de la enfermedad.
La Neuropatía endémica asociada con el Virus Humano Linfotrópico de Celulas T-tipo 1, (NEC-HTL V-1 es una enfermedad lentamente progresiva caracterizada por debilidad de las extremidades inferiores, trastornos de los esfínteres, alteraciones subjetivas de la sensibilidad, asociadas con la presencia de anticuerpos contra el HTL V-I en la sangre y en el líquido cefalorraquídeo.
La enfermedad fue descrita por primera vez hace casi cien años en Jamaica por Strachnan (1897, Cruishank publicó en 1956 el cuadro patológico en el cual se encuentra degeneración de las vías piramidales, desmielinización, proliferación capilar con acúmulos de linfocitos alrededor de los vasos sanguineos. Maní y col informaron una enfermedad similar en el Sur de la India (1969. En 1981 Zaninovich encontró una zona endémica en la costa del Pacífico de Colombia y gracias a su interes consiguió apoyo de la Organización Mundial de la Salud y del Instituto Nacional de Salud de los Estados Unidos para adelantar los estudios sobre esta endemia.
En 1985 Gessain y col hallaron por primera vez en Martinfca anticuerpos contra el HTL V-1 en una alta proporción de pacientes con la enfermedad que denominaron Paraparesia Espástica Tropical.
El Virus Humano Linfotrópico de Celulas T o HTL V-1, pertenece a la familia de los Retrovirus, caracterizados por poseer una enzima denominada Transcriptasa Invertida (“Reverse Transcriptase”. Fue descubierto por Gallo
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Energy Technology Data Exchange (ETDEWEB)
Smith, C. L. [Department of Radiotherapeutics, University of Cambridge, Cambridge (United Kingdom)
1962-02-15
lesions subies par la structure type de l'ADN (ou du phosphate de l'ADN) pendant la phase exponentielle dela synthese, les observations formulees plus haut sous 1, 2 et 3 constituent les corollaires evidents de ce phenomene. (author) [Spanish] La memoria describe los efectos de las particulas {alpha} y de los rayos X sobre la velocidad de sintesis del ADN en cultivos de tejidos de fibroblastos y de celulas de HeLa del raton. Los autores emplearon el metodo de la microautorradiografia con timidina tritiada, que les permitio evaluar la velocidad de sintesis en los cultivos de una sola capa que utilizaron. Los resultados indican que: 1) La fraccion de celulas que sintetizan ADN en un cultivo no es alterada por las particulas a. ni por los rayos X en las dosis experimentales empleadas. 2) Ambos tipos de radiaciones reducen la velocidad de sintesis del ADN en las celulas irradiadas. 3) El efecto de una dosis determinada de cualquiera de las dos radiaciones es disminuir la velocidad de sintesis de todas las celulas hasta una fraccion constante de la velocidad correspondiente a las celulas no irradiadas. 4) En. el caso de los fibroblastos del raton, la velocidad de sintesis del ADN queda reducida en un 37 por ciento (1/e) por una dosis a del orden de 25 {alpha}/{mu}{sup 2} o por una dosis de rayos X de 14 000 rad( En el caso de las celulas de HeLa, se requiere una dosis de unos 90 000 rad para alcanzar el mismo efecto. 5) La disminucion de la velocidad de sintesis se produce menos de media hora despues de la irradiacion, por lo que podria tratarse de un efecto inmediato. El resultado 4) permite calcular aproximadamente la forma del blanco. Si seo supone que es cilindrico, enoel caso de los fibroblastos, tendria un diametro aproximado de 16 A y una longitud de 16 000 A, es decir, se trataria de un cilindro extremadamente alargado con un peso molecular del orden de 5 x 10{sup 7}. Para las celulas de HeLa se obtendria un peso molecular de 10{sup 7}. Los resultados concuerdan con la
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Energy Technology Data Exchange (ETDEWEB)
Boaventura, Jaime S.; Aguiar, Aurinete B.; Brandao, Soraia T. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Frank, Maria Helena Troise; Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil)
2004-07-01
Electro-catalysts were prepared using new routes. Chemical Ultrasound Deposition (CUD) method: aqueous solution of nickel nitrate and citric acid was ultrasound vaporized and deposited on heated Ytria-stabilized Zirconia (YSZ). Resin impregnation (IPR) method: nickel oxide and YSZ were mixed, added to phenolic resins, precipitated in acidic water and milled. Wet impregnation method (IMP) was used for comparison: YSZ and an aqueous solution of nickel nitrate and citric acid were mixed, followed by evaporation, drying and calcination. The catalysts were evaluated for methane steam reforming in a quartz reactor. The reactions were conducted for one hour with no significant catalytic activity loss. In reactions with 100 mg of catalyst and a mixture consisting of methane and steam (3:1), IPR catalyst showed activity higher and better stability than those by IMP. On other tests, the reform was conducted with 100 mg of catalyst and methane to steam of 10. The IPR catalyst activity was so high that the reaction approached equilibrium conditions. Anode/electrolyte/cathode units (A/E/C) were prepared with the above catalysts as follows: the anode was a catalyst porous layer; the electrolyte an YSZ dense layer; and the cathode an LSM porous layer; graphite powder formed the material porosity. The two first layers, in powder form, were put in a stainless steel cast, pressed to 4000 bars and sinterized. The cathode layer was subsequently added using tape-casting techniques followed by sintering. A/E/C units showed 40% linear contraction and porosity higher than 20%. For fuel cell tests, A/E/C was mounted in alumina plates with platinum current collectors. Unitary SOF cells were loaded with hydrogen diluted in nitrogen showing opened circuit voltage from circa 700 mV, for the CUD anode, to 350 mV, for the IPR anode. The unitary SOFC was loaded with methane for 15 minutes or longer, with no noticeable voltage loss. At 1300 K the SOFC made with IPR or IMP catalysts showed opened current voltages close to 500 mV, while CUD SOFC measured less approximately 300 mV. In conclusion, the SOFC opened current voltage might be related to the reforming activity of the electro-catalyst used as the anode. (author)
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Clinical applications of cells labelling; Aplicaciones clinicas del marcado de celulas
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, B M [Instituto Nacional de Pediatria (Mexico)
1994-12-31
Blood cells labelled with radionuclides are reviewed and main applications are described. Red blood cell labelling by both random and specific principle. A table with most important clinical uses, 99mTc labelling of RBC are described pre tinning and in vivo reduction of Tc, in vitro labelling and administration of labelled RBC and in vivo modified technique. Labelled leucocytes with several 99mTc-complex radiopharmaceuticals by in vitro technique and specific monoclonal s for white cells(neutrofiles). Labelled platelets for clinical use and research by in vitro technique and in vivo labelling.
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Terapêutica do carcinoma pulmonar não de pequenas celulas
Directory of Open Access Journals (Sweden)
Renato Sotto-Mayor
2002-05-01
Full Text Available RESUMO: No presente artigo de revisão o autor aborda a terapêutica do carcinoma pulmonar nao de pcquenas células em função do estádio de apresentação da doença, dando especial relevo à sua abordagem multidisciplinar, no sentido de ultrapassarmos o mau prognóstico que o seu diagnóstico ainda acarreta.Discute o Iugar das diferentes modalidades terapêuticas, a terapeutica da recidiva e da progressão tumorais, a do cancro do pulmao no doente idoso, o papel dos novos fármacos e as potencialidades dos novos alvos terapêuticos a nivel da biologia celular e molecular.REV PORT PNEUMOL 2002; Vlll (3: 237-259 ABSTRACT: In the present paper, the author reviews the non-small-cell lung cancer treatment by stages of disease.He states about the therapeutic strategies involving surgery, radiation therapy and chemotherapy, the important role of the multimodality approach of the patients, the relapsing and refractory tumor, the elderly patient, the new drugs, and the potential role of new gene and cell -based therapies.REV PORT PNEUMOL 2002; VIII (3: 237-259 Palavras-chave: carcinoma do pulmão, terapêutica, Key-words: Lung cancer, therapeutic
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Energy Technology Data Exchange (ETDEWEB)
Negrini, Aguinaldo Donizete
2010-07-01
The {sup 67}Ga is an important radiopharmaceutical used to identify inflammatory processes in chronic illnesses, diagnosis by image of tumors in soft tissues and the possibility to evaluate the result for therapeutic intervention. In the present work a module of {sup 67}Ga processing was developed with the objective to reduce the interventions in the hot cell, in order to avoid oxidation caused by metallic materials, and consuming in hoses of the peristaltic pumps, that release residues that blocked the valves used in the process. With materials such as: acrylic, PVC, PEEK e teflon and they are used vacuum as method (way) of fluid transferences instead of peristaltic pump in the majority of the procedures, with this improvements the system can make shorter the lengths of transference hoses, increasing the yield in the process with less interventions for maintenance and time exposure of the workers, guaranteeing the quality and reducing the time of the processing. using a mobile system for displacement of the processing module making in the cleanness and maintenance of the cell that works with radioactive material. Reducing the time of exposure dose of the workers in compliance with RDC-17 of ANVISA, which ruling the Good Manufacturing Practice Procedures. (author)
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En búsqueda de marcadores de celulas madre mesenquimales de la pulpa dental
Merino, Graciela; Dewey, Ricardo; Mayocchi, Karina; Butler, Teresa Adela; Dorati, Pablo; Basal, Roxana Lía; Paggi, Ricardo; Cantarini, Martín; Pinola, Lidia; Micinquevich, Susana
2016-01-01
Al plantearse aislar y cultivar células madre de la pulpa dental, es Importante conocer sus características morfológicas, inmunohistoquímica, ultraestructurales y moleculares. Respecto a la inmunohistoquímica se conocen moléculas marcadoras ubicadas en la superficie celular. Ellas tienen la propiedad de reconocer determinados anticuerpos. Las siglas utilizadas para su Identificación se reconocen como CD (Cluster of Differentiation). El objetivo del presente trabajo fue diseñar una tabla, en b...
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Efficiency of SOFC type fuel cells; Eficiencia de celulas combustiveis do tipo SOFC
Energy Technology Data Exchange (ETDEWEB)
Amaral, Alexandre Alves do; Matos, Francisco F.; Boaventura, Jaime S.; Benedicto, Joao Paulo S.; Alencar, Marcelo [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica
2006-07-01
production of electric energy, mainly due to the fact that it is virtually no pollutant. Typically, the SOFC is constituted of at least seven distinct phases: fuel, anode, electrolyte substrate (separating the two electrodes), cathode, air, and electrical inter connectors (completing the electrical circuit). Thermodynamics clearly shows that electrochemical systems only can be reversible when homogeneous, what it is not case of the Sofc. Therefore, the application of equilibrium thermodynamics to these systems is incorrect. This work proposes that the Sofc can be better depicted from reactions between adsorbed species. The efficiency then is calculated as the ratio between the free energy of these reactions to the combustion heat. Thermodynamic parameter estimative is developed for the global and adsorbed species reactions. (author)
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La formación actual del médico: fortalezas y debilidades
Directory of Open Access Journals (Sweden)
X. Clèries
Full Text Available Las “Jornadas estatales de estudio y debate sobre el futuro de la formación integral del médico ¿bioingeniería o medicina?” que se realizaron en Barcelona el 8 y 9 de febrero de 2008 fueron el marco para que un grupo de trabajo abordara el tema de las fortalezas y debilidades de la formación actual del médico. Las principales aportaciones se estructuraron en los tres niveles educativos siguientes: pregrado, posgrado y formación continuada. Se destacó la necesidad de una formación integral y psicosocial en la enseñanza de pregrado, la conveniencia de una estructuración troncal de la formación de posgrado para conseguir una mayor transversalidad de la competencia del médico y la contextualización de la formación continuada en el desarrollo profesional de cada médico. El predominio de los conocimientos biomédicos y tecnológicos en la formación actual del médico contrastan con las demandas de carácter psicosocial de una gran parte de la población en el sistema sanitario.
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Modeling and simulation of PEM fuel cell's flow channels using CFD techniques
Energy Technology Data Exchange (ETDEWEB)
Cunha, Edgar F.; Andrade, Alexandre B.; Robalinho, Eric; Bejarano, Martha L.M.; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: efcunha@ipen.br; abodart@ipen.br; eric@ipen.br; mmora@ipen.br; mlinardi@ipen.br; Cekinski, Efraim [Instituto de Pesquisas Tecnologicas (IPT-SP), Sao Paulo, SP (Brazil)]. E-mail: cekinski@ipt.br
2007-07-01
Fuel cells are one of the most important devices to obtain electrical energy from hydrogen. The Proton Exchange Membrane Fuel Cell (PEMFC) consists of two important parts: the Membrane Electrode Assembly (MEA), where the reactions occur, and the flow field plates. The plates have many functions in a fuel cell: distribute reactant gases (hydrogen and air or oxygen), conduct electrical current, remove heat and water from the electrodes and make the cell robust. The cost of the bipolar plates corresponds up to 45% of the total stack costs. The Computational Fluid Dynamic (CFD) is a very useful tool to simulate hydrogen and oxygen gases flow channels, to reduce the costs of bipolar plates production and to optimize mass transport. Two types of flow channels were studied. The first type was a commercial plate by ELECTROCELL and the other was entirely projected at Programa de Celula a Combustivel (IPEN/CNEN-SP) and the experimental data were compared with modelling results. Optimum values for each set of variables were obtained and the models verification was carried out in order to show the feasibility of this technique to improve fuel cell efficiency. (author)
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Modeling and simulation of PEM fuel cell's flow channels using CFD techniques
International Nuclear Information System (INIS)
Cunha, Edgar F.; Andrade, Alexandre B.; Robalinho, Eric; Bejarano, Martha L.M.; Linardi, Marcelo; Cekinski, Efraim
2007-01-01
Fuel cells are one of the most important devices to obtain electrical energy from hydrogen. The Proton Exchange Membrane Fuel Cell (PEMFC) consists of two important parts: the Membrane Electrode Assembly (MEA), where the reactions occur, and the flow field plates. The plates have many functions in a fuel cell: distribute reactant gases (hydrogen and air or oxygen), conduct electrical current, remove heat and water from the electrodes and make the cell robust. The cost of the bipolar plates corresponds up to 45% of the total stack costs. The Computational Fluid Dynamic (CFD) is a very useful tool to simulate hydrogen and oxygen gases flow channels, to reduce the costs of bipolar plates production and to optimize mass transport. Two types of flow channels were studied. The first type was a commercial plate by ELECTROCELL and the other was entirely projected at Programa de Celula a Combustivel (IPEN/CNEN-SP) and the experimental data were compared with modelling results. Optimum values for each set of variables were obtained and the models verification was carried out in order to show the feasibility of this technique to improve fuel cell efficiency. (author)
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Directory of Open Access Journals (Sweden)
Adriana del Pilar López Lombana
1993-12-01
Full Text Available La célula de Schwann que constituye la glía del SNP, además de ser el soporte estructural para los axones en dicho sistema, tiene la función de producir la mielina, una organela de gran importancia en los procesos de neuroconducción. De la integridad de esta célula dependen el desarrollo estructural y metabólico del axón, así mismo se ha reconocido desde hace varios anos el papel primordial que juega ella, en los procesos de regeneración del SPN posterior a una injuria, en cuyo caso reinician la proliferación para producir una guía de regeneración del nervio periférico. En esta revisión se contemplarán algunos de los puntos relacionados con su origen, desarrollo, estructura, relación con el axon y el tipo de patologías que pueden alterarla; igualmente se resalta la utilidad de los cultivos de celulas de Schwann para el estudio de los procesos de mielinización, desmielinización, regeneración post-traumatica y respuesta a agentes infecciosos.
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Algumas investigações sobre Schizotrypanum de Quirópteros
Directory of Open Access Journals (Sweden)
Emmanuel Dias
1939-01-01
Full Text Available Os autores referem as especies de morcegos de diversos países americanos, emque foi pesquisada no sangue a presença de hemoflagelados. Tripanosomas com a morfologia das formas sanguicolas de Schizotrypanum foram encontrados, tendo sido colhidos dados novos sobre a distribuição geografica e a incidencia da infecção em diferentes especies de morcegos. Sómente nos tecidos do Phyllostomus hastatus puderam ser encontradas as formas de multiplicação do flagelado. Alimentando-se exemplares de Triatoma infestans em Eumops bonariensis beckeri infectado, foi obtido desenvolvimento intestinal do parasito. Por inoculação das vinchucas assim infectadas em camondongo, conseguiu-se facilmente transmissão da infecção a este animal. Inoculando-se cultura do Schizotrypanum de Phyllostomus hastatus em coelho, por via subcutanea, verificaram-se no ponto de inoculação, 5 dias depois, celulas contendo tipicas formas de leishmania. São assinalados fatos observados sobre a associação demorcegos com Hemipteros sugadores (Reduvideos e Cimicideos, os quais, pela circunstancia de se poderem infectar pelo flagelado, são os possiveis transmissores da infecção a estes mamiferos.
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Energy Technology Data Exchange (ETDEWEB)
Anger, Hal O; Rosenthal, Donald J [Lawrence Radiation Laboratory and Donner Laboratory of Biophysics and Medical Physics University of California, Berkeley, CA (United States)
1959-07-01
A short description is given of earlier forms of the gamma-ray camera. The principle of operation of the scintillation camera is reviewed. Here the locations of scintillations occurring in a flat thallium-activated sodium iodide crystal are determined from the amount of light picked up by a number of phototubes simultaneously viewing the crystal. The signals from the phototubes are fed to a deflection computor circuit which reproduces the scintillations on a cathode-ray tube screen. There they are photographed by a conventional scope camera. Examples are shown of the resolution now obtained as shown by test phantoms. A discussion is presented of the camera's use in visualizing the thyroid in clinical practice. (author) [French] Les auteurs donnent une breve description des gammametres photographiques employes anterieurement. Ils rappellent le principe du fonctionnement du scintillometre photographique. Cet appareil permet de localiser des scintillations emises par un cristal plat d'iodure de sodium active au thallium d'apres le flux lumineux capte par plusieurs cellules photoelectrique s placees devant le cristal. Des cellules photoelectriques, les signaux sont transmis a un circuit de comptage a deviation qui reproduit les scintillations sur l'ecran d'un tube a rayons cathodiques. Elles sont ensuite photographiees a l'aide d'un appareil ordinaire. Au moyen de
, les auteurs donnent des exemples du pouvoir de resolution qu'il est possible d'obtenir maintenant. Ils etudient l'utilisation du dispositif pour la representation visuelle de la thyroide dans la pratique clinique. (author) [Spanish] El trabajo ofrece una breve description de las camaras de rayos gamma utilizadas anteriormente. Se pasa revista al principio de funcionamiento de la camara de centelleo. Ese aparato permite localizar los destellos emitidos por un cristal piano de yoduro de sodio activado por talio, en funcion del flujo luminoso captado por cierto numero de celulas fotoelectricas -
Energy Technology Data Exchange (ETDEWEB)
Timbo, Christiano dos Santos
2004-07-01
This method relies on the application of an algorithm for the quantitative and statistic differentiation of a sample of cells stricken by a certain kind of pathology and a sample of healthy cells. This differentiation is made by applying the principles of fractal dimension to digital images of the cells. The algorithm was developed using the the concepts of Object- Oriented Programming, resulting in a simple code, divided in 5 distinct procedures, and a user-friendly interface. To obtain the fractal dimension of the images of the cells, the program processes the image, extracting its border, and uses it to characterize the complexity of the form of the cell in a quantitative way. In order to validate the code, it was used a digitalized image found in an article by W. Bauer, developer of an analog method. The result showed a difference of 6% between the value obtained by Bauer and the value obtained the algorithm developed in this work. (author)
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Belchor, P.M.; Forte, M.M.C. [Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Correa, J.P.; Kuhn, C.K.; Carpenter, D. [FURB -Fundacao Universidade Regional de Blumenau, SC (Brazil)
2010-07-01
This paper aimed to compare the performance of a CCADE and a CCADM as function of diminishing of concentration of alcohol applied top the anode of each cell. As result, reaching a diminishing the concentration of each alcohol through the mix of each one with the deionized water, one obtained a improved humidification and sensible reduction of the permeability of cationic membrane, generating a gain of performance of the functioning both cells. (author)
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Directory of Open Access Journals (Sweden)
Isabel Mª Manzano Pérez
2005-01-01
Full Text Available El objetivo del presente trabajo consiste en suscitar el debate en torno a algunos de los cambios en la práctica docente que conllevará la aproximación a la filosofía de la convergencia europea. En concreto, expondremos una propuesta de elaboración de una Guía Aprendizaje Orientado para el estudio de la Programación Lineal, tema de la asignatura troncal del segundo curso de la Licenciatura en Administración y Dirección de Empresas: Métodos Matemáticos para la Administración y Dirección de Empresas. La Guía de Aprendizaje Orientado propuesta dirigirá al alumno en la profundización y ampliación de los contenidos planteados en las clases presenciales incentivándole en la realización de diversas actividades prácticas relacionadas con la materia objeto de estudio. Para ello la Guía debería en primer lugar, permitir al alumno conocer con detalle cuáles son los objetivos de conocimiento y cuáles son las competencias que se espera adquiera cursando el tema objeto de estudio. Por último, pero no por ello menos importante, la Guía debe facilitar al alumno el control del grado de adquisición de conocimientos a lo largo del tema.
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Santillan, M.; Angulo-Brown, F.; Chavoya-Aceves, O. [Instituto Politecnico Nacional, Mexico, D. F. (Mexico)
2001-04-01
The definitions of power and efficiency for energy-converting intracellular biochemical processes, introduced by Caplan and Essig are studied. These definitions are recovered in the present work with the formalism of De Groot and Mazure for First-Order Irreversible Thermodynamics, rather than the formalism of Prigogine, as done by Caplan and Essig. The approach here employed permits to keep track of all the assumptions in a more clear manner, and to get rid of a very strong restriction in the approach of Caplan and Essig which assumes that the chemical potentials are homogeneous inside the cell. [Spanish] Se estudian las definiciones de potencia y eficiencia para procesos bioquimicos intracelulares convertidores de energia, introducidas por Caplan y Essig. En el presente trabajo, dichas definiciones se recuperan usando el formalismo de De Groot y Mazur para la termodinamica irreversible de primer orden, en vez del formalismo de Prigogine, empleado por Caplan y Essig. El punto de vista empleado en el presente manuscrito permite seguir las suposiciones hechas de una manera mas clara, ademas de que hace innecesaria una suposicion bastante fuerte usada por Caplan y Essig, la cual da por hecho que los potenciales quimicos son homogeneos en el interior de la celula.
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Energy Technology Data Exchange (ETDEWEB)
Rubini, J. R.; Keller, S.; Eisentraut, A. [Veterans Administration Hospital and Southwestern Medical School, Dallas, TX (United States); Cronkite, E. P. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)
1962-02-15
petites quantites de thymidine tritiee; il n'y a pas de formation d'eau tritiee. Les auteurs formulent des hypotheses concernant les mecanismes qui entrent en jeu. (author) [Spanish] Los autores han estudiado el metabolismo y comportamiento in vitro de la timidina tritiada ({sup 3}HTDR; 1,9 curies/mM), que es un precursor del acido desoxirribonucleico, en sangre de enfermos de leucemia y en medula normal de perro. Para evaluar la cantidad de acido desoxirribonucleico recientemente sintetizado determinaron los indices de marcacion y contaron los granulos de autorradiogramas de celulas, tomadas una hora despues de la marcacion. La marcacion de las celulas pudo atenuarse facilmente anadiendo al principio a la timidina tritiada pequenas cantidades de timidina sin marcar, con lo que se demuestra que el espacio de timidina es muy reducido. Si al cabo de 20 minutos se anade timidina a la mezcla en incubacion, la marcacion no se atenua. Este periodo de 20 minutos define el periodo de incorporacion de la timidina tritiada. Al cabo de una hora, la actividad del {sup 3}H contenido en el liquido sobrenadante era aun considerable, pero no suficiente para marcar nuevas celulas anadidas. Este liquido sobrenadante 'gastado' contiene {sup 3}HTDR como principal compuesto tritiado y solo pequenas cantidades de timina-{sup 3}H ; no se formo agua tritiada. Los autores formulan hipotesis acerca de los mecanismos que intervienen en estos fenomenos. (author) [Russian] Izuchalsja metabolizm in vitro i sud'ba pervichnoj chasticy DNK N( timidina, N{sup 3} TshJa (1.9 C{mu}/M) v lejkemichnoj krovi cheloveka i mozgah normal'noj sobaki. Predvaritel'nyj podschet novogo sinteza DNK proizvodilsja mechashhimi indeksami i otschetom zeren avtoradiogramm kletok poluchennyh iz smesej v techenie odnogo chasa. Mechenie kletok mozhet byt' bystro ponizheno dobavleniem minutnyh kolichestv nemechenogo TDR pervonachal'no k H{sup 3} TDR, demonstriruja neznachitel'nost' pula TDR. Kogda TDR, 20 minut spustja byl
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Nunes, Suzana Pereira [GKSS-Forschungszentrum, Geesthacht (Germany)]. E-mail: nunes@gkss.de
2005-07-01
Membranes for fuel cell were prepared using as polymer matrix sulfonated polyether ketones. New sulfonated copolymers (poly oxazoles, poly imides and poly ketones) were synthesized. Nano composites using zirconium oxide and phosphates, as well as modified silicates were obtained aiming the application on direct methanol fuel cell (DMFC). The performances of membranes containing fillers with different aspects (spherical, layers, tubular, networks) and surface modification (hydroxy, imidazole, acid oligomers) were compared. The effect of surface modification was much more pronounced than that of the aspect. A good balance of proton conductivity and methanol permeability was obtained with silicates modified with imidazole groups. Good performance in DMFC were obtained with membranes containing zirconium phosphate. Acid oligomers also led to particularly high conductivity values above 100 deg C. Polyimide membranes with H{sub 2}/CH{sub 4} larger than 100 were obtained. (author )
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Energy Technology Data Exchange (ETDEWEB)
Gonzalez, E.R.; Avaca, L.A.; Ticianelli, E.A.; Ferreira, A.C.; Oliveira, J.C.T. de [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica
1984-12-31
This work describes the main steps for the development of the components of an one-kilowatt phosphoric acid H{sub 2}/O{sub 2} fuel cell stack. The electrochemical characteristics of fundamental components-electrodes and electrolyte-matrix have been evaluated in unitary fuel cell prototype by stationary polarization curves and continuous operation curves. The results confirmed the better efficiency of the hydrogen electrode and anticipated a very fair performance for the one-kilowatt stack. (author). 4 figs., 5 refs
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Directory of Open Access Journals (Sweden)
Pedro Emilio García
Full Text Available Resumen: El adenocarcinoma de células basales es una neoplasia epitelial con las características citológicas del adenoma de células basales pero con un patrón morfológico de crecimiento infiltrante indicativo de malignidad. Debido a su baja incidencia es a menudo difícil de diagnosticar. El objetivo del presente estudio fue identificar características morfológicas e inmunohistoquímicas que contribuyen a su diagnóstico. Se resecó un tumor de parótida en una paciente de 52 años; se realizó biopsia postoperatoria e inmunomarcación con Ki-67, CK19, p63 y alfa actina de músculo liso. Se diagnosticó adenocarcinoma de células basales mixto sólido y tubular con invasión perineural y de la cápsula tumoral, grasa periglandular y nodos linfoides. La inmunomarcación con Ki-67, CK19, p63 y alfa actina de músculo liso resultó positiva. Posteriormente se diagnosticó una metástasis en seno maxilar. Las características morfológicas, la inmunomarcación Ki-67 positiva y la metástasis le dan el carácter maligno a este tumor, lo que lo diferencia del adenoma de células basales.
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Energy Technology Data Exchange (ETDEWEB)
Gonzalez, E R; Avaca, L A; Ticianelli, E A; Ferreira, A C; Oliveira, J C.T. de [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica
1985-12-31
This work describes the main steps for the development of the components of an one-kilowatt phosphoric acid H{sub 2}/O{sub 2} fuel cell stack. The electrochemical characteristics of fundamental components-electrodes and electrolyte-matrix have been evaluated in unitary fuel cell prototype by stationary polarization curves and continuous operation curves. The results confirmed the better efficiency of the hydrogen electrode and anticipated a very fair performance for the one-kilowatt stack. (author). 4 figs., 5 refs
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Directory of Open Access Journals (Sweden)
García Pérez, Emilia
2001-01-01
Full Text Available Acabamos de finalizar el año mundial de las matemáticas y su influencia todavía perdura. El pasado 17 de Enero, en el Círculo de Bellas Artes de Madrid, podíamos oír al crítico francés George Steiner (1929 en su conferencia sobre la crisis del lenguaje frases como “el habla ya no es la definición del ser humano, debido a que parece obligado a entregarse al lenguaje de las matemáticas”, y recordó que Galileo ya comentaba que “la naturaleza se expresa por las matemáticas, no a través de las lenguas”. Nadie duda de la importancia e utilidad de las matemáticas en el mundo en que vivimos y por consiguiente en los estudios en economía y en ADE. El problema surge a la hora de elegir qué conceptos matemáticos son realmente imprescindibles para cursar las mencionadas licenciaturas. En este trabajo se pretende justificar los contenidos de los créditos de matemáticas en el resto de las asignaturas de las licenciaturas en economía y en ADE según sus necesidades. El trabajo se presenta en tablas, una para cada asignatura (troncales y optativas, y para ambas licenciaturas. Por último se realiza el comentario de las aplicaciones concretas a diversas asignaturas del plan de estudios.
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Lúcia Maria C. Galvão
1981-09-01
Full Text Available Formas de cultura de diferentes cepas do T.cruzi foram submetidas a vários processos de criopreservação. As percentagens de recuperação, avaliadas pela motilidade dos parasitas, foram consideradas como adequadas com algumas das técnicas empregadas, variando entre 60 a 80%. A estabilidade das características biológicas do material criopreservado foi investigada através do estudo das curvas de crescimento e diferenciação em meio acelular, infectividade para celulas de cultura de tecido ("Vero", diferenciação intracelular em cultura de tecido assim como infectividade e curso da infecção em animais de laboratório. De um modo geral essas características nao foram significativamente alteradas no material congelado e estocado por diferentes períodos de tempo.A systematic study of the cryopreservation of T. cruzi culture forms was per formed using different parasite strains and freezing methods. The recovery rates with some of the methods as evaluated by motility of the thawed parasites were fairly high (60-80%. The following aspects have been used to investigate the stability of the parasites' biological characteristics atter cryopreservation: growth and differentiation in acelular medium, infectivity to tissue culture "Vero" cells, intracellular differentiation and infectivity to animals. Those characteristics had not been significantly changed by the cryopreservation procedures.
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Linfoma primario del sistema nervioso central en una paciente con lupus eritematoso sistémico
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C. N. Pisoni
2003-06-01
Full Text Available Se presenta una paciente de 36 años con diagnóstico de lupus eritematoso sistémico tratada con prednisona y ciclofosfamida que se internó por cefalea, hemiparesia y hemianestesia braquiocrural derecha de dos semanas de evolución. Se realizó una tomografía computada y una resonancia magnética nuclear de cerebro que mostraron una lesión nodular frontal izquierda. Se efectuó una biopsia a cielo abierto de la lesión cerebral cuyo diagnóstico histopatológico fue linfoma B de celulas grandes, difuso. Se inició radioterapia, no completó el tratamiento por complicaciones y falleció. Son muy pocos los casos publicados de linfoma primario del sistema nervioso central asociado a lupus eritematoso sistémico.A 36 year-old woman with systemic lupus erythematosus was admitted to our hospital with headache, brachiocrural hemiparesis and hemianesthesia. She had been treated with prednisone and cyclophosphamide. CT scan and MRI revealed a 15 mm nodular mass enhanced with gadolinium in left frontal convexity. CNS biopsy was performed and a diffuse large B-cell lymphoma was diagnosed. She was treated with radiation therapy without response and died. There are few reports of erythematosus systemic lupus associated with primary central nervous system lymphoma.
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Energy Technology Data Exchange (ETDEWEB)
Boaventura, Jaime S.; Alencar, Marcelo Goncalves F. de; Amaral, Alexandre Alves do; Benedicto, Joao Paulo Santos; Silva, Marcos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica
2006-07-01
Fuel cells allow the energy production without the thermodynamic restriction of the conversion of heat into work. Among their various types, the solid oxide fuel cells (SOFC), operating at high temperatures, allow the methane conversion into electricity directly on the anode. The main element of the SOFC is the structure A/E/C: anode/electrolyte/cathode, all sintered at high temperature as resistant ceramic materials. Dense electrolyte (YSZ: zirconia stabilized for Yttria) separates the anode (Ni+Co/YSZ: cobalt promoted nickel, supported on YSZ) and cathode (LSM: strontium-doped lanthanum manganite), both with porosity obtained by graphite addition. To obtain suitable A/E/C pellets, the layer sintering with appropriate mechanical and textural characteristics is essential, requiring excellent electric junctions between them. The cell performance has been evaluated between 850 and 950 degree C, using hydrogen or methane fuel; the tension and current for different resistance values in the electrical circuit have been measured. The cobalt addition to the cell anode significantly increased its activity for the reform reaction. The beneficial effect was probably due to the easier nickel reduction in cobalt presence. This work had the objectives of developing and evaluating electro-catalysts, as well as the solid oxide fuel cells using these catalysts as anode. Five SOFC models (SOFC 1 to SOFC 5) are described; all of them were developed aiming at improving the preparation of the anode/electrolyte/cathode structure (A/E/C). (author)
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Energy Technology Data Exchange (ETDEWEB)
Sprenger, Humberto Elias [Programa de Pos-graduacao em Desenvolvimento de Tecnologia (PRODETEC/LACTEC/IEP), Cutitiba, PR (Brazil); Cantao, Mauricio Pereira [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], E-mail: mauricio.cantao@utp.br
2010-10-15
Waste water treatment stations using upflow anaerobic sludge blanket (UASB) produce biogas, composed of carbon dioxide diluted methane plus minority compounds. This kind of reactor is worthwhile but demands methane burning in order to reduce atmospheric pollution and damage to ozone layer. Meanwhile, biogas can be used for energy generation due to its heating value. In this paper a technical and economic feasibility study about the use of biogas as a hydrogen source for fuel cells feeding is presented. Two methods for assessment of biogas production in UASB reactor were compared for ETE Atuba Sul case. (author)
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La docencia universitaria en el proceso de adaptación a Europa: la percepción de los estudiantes
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María Luisa RODICIO GARCÍA
2011-04-01
Full Text Available En este artículo presentamos parte de un estudio llevado a cabo con estudiantes de la Universidad de A Coruña (udc en el que tratamos de conocer su percepción acerca de la docencia que reciben, planificada según las directrices de bolonia. En un primer momento se trabaja con todos los estudiantes de la titulación de Psicopedagogía a los que se les preguntaba sobre diferentes cuestiones relativas a la adaptación de las materias a créditos ecTs así como su percepción del proceso que se está generando en las Universidades y, en una segunda fase, se pulsa la opinión de los estudiantes de una asignatura concreta. Nuestra aportación, en esta ocasión, se centra en esa segunda fase y, concretamente, en la investigación llevada a cabo con los estudiantes que cursan la materia «Modelos de Orientación e Intervención Psicopedagógica», asignatura troncal del primer curso de la titulación de Psicopedagogía (n = 20. La metodología utilizada es de corte cualitativo, utilizando la entrevista estructurada como técnica de recogida de datos. Los resultados nos permiten concluir que los cambios que propugna la Reforma son del agrado de los estudiantes, sintiéndose más y mejor orientados y más activos en su proceso de aprendizaje.
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Células tronco mesenquimales: definiciones, cultivo y aplicaciones potenciales
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Willy Ceron
Full Text Available En los últimos años, las células troncales mesenquimales (Mesenchymal Stem Cells, MSC han adquirido mucha importancia debido a su gran plasticidad y su capacidad de liberar factores paracrinos con capacidad de interactuar con diversos tipos celulares, tejidos y órganos. El uso de MSC en medicina regenerativa es importante debido a que, al no expresar las moléculas del complejo mayor de histocompatibilidad (MHC clase II ni moléculas co-estimuladoras y tener baja expresión del MHC clase I, haría que no sean rechazadas por individuos de la misma especie, es posible utilizarlas no sólo de manera autóloga, sino también, eventualmente, alogénica. Sin embargo, es importante demostrar científicamente muchas de sus propiedades, entre ellas las inmunomoduladoras. Al tener varias fuentes de obtención, se debe estandarizar la que sea la mejor para garantizar la pureza y calidad de las MSC. Finalmente, es importante que cuando se trabaje con estas células se demuestre completamente las características del cultivo celular, la inmunotipificación y su capacidad de diferenciación. Se están ensayando muchas aplicaciones clínicas de las MSC. Dentro de ellas, su capacidad para mejorar la recuperación y potencial curación de úlceras crónicas como las diabéticas, ha atraído la atención por su potencial impacto terapéutico.
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ÍNDICE DE SITIO PARA PLANTACIONES DE Pinus greggii Engelm. EN METZTITLÁN, HIDALGO, MÉXICO
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Jonathan Hernández-Ramos
2014-01-01
Full Text Available L os índices de productividad son esenciales en la planeación del manejo forestal sustentable. El índice de sitio es la metodología más utilizada en la clasificación de la calidad de las áreas forestales. Sin embargo, la mayoría de los macizos forestales y plantaciones no cuentan con tal información que apoye la planeación de las actividades silvícolas. Por ello, el objetivo fue estimar el índice de sitio de las plantaciones forestales de Pinus greggii Engelm., establecidas en la parte serrana del municipio de Metztitlán, Hidalgo. Los modelos de Schumacher, Chapman-Richards y Wei - bull se ajustaron con 233 observaciones de edad-altura provenientes de un análisis troncal. De acuerdo con el valor más bajo del cuadrado medio del error, el valor más alto de R 2 y la distribución de residua - les, se seleccionó el modelo de Schumacher para la construcción de la curva guía y el sistema de curvas anamórficas y polimórficas. Se establecieron cinco etiquetas de índice de sitio para las alturas 12, 14, 16, 18 y 20 m con calidades de estación V, IV, III, II y I, respectivamente. Se obtuvo buena estimación del crecimiento de la altura dominante en función de la edad, ya que considera todas las condiciones existentes dentro de las plantaciones.
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Células madre: limitaciones y oportunidades en el Perú
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José Amiel-Pérez
Full Text Available Las células madre o células troncales (stem cells, en inglés se definen como células poco frecuentes que poseen las características de dividirse asimétricamente mediante un proceso conocido como autorrenovación, y su potencial para distinguirse en más de un tipo de célula terminalmente diferenciada. Existen diversos tipos de células madre los cuales incluyen: las células madre embrionarias, que existen solo en las primeras etapas del desarrollo y varios tipos de células madre adulta que, a su vez, incluyen tejidos específicos o derivados de tejidos estromales o mesenquimales. Asimismo, se pueden generar por ingeniería genética, células con propiedades similares a las células madre embrionarias, pero derivadas de tejidos adultos y sin limitaciones éticas y legales que se denominan células madre pluripotentes inducidas. En todos estos casos, existen muchas incógnitas que se siguen trabajando en la ciencia básica para informar mejor a la práctica clínica. En el Perú se están afinando técnicas y mejorando metodologías que aún requieren perfeccionamiento, mejor equipamiento y mayor especialización de los recursos humanos, pero constituyen un loable esfuerzo en favor de una destacada posición internacional y el desarrollo futuro en el área de células madre
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¿Por qué enseñar métodos de investigación en las facultades de Biblioteconomía y Documentación?
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Emilio Delgado López-Cózar
2001-01-01
Full Text Available Se pretende demostrar por qué es necesaria la enseñanza de métodos de investigación en los estudios de Biblioteconomía y Documentación. Se exponen las opiniones al respecto de diversos profesionales, profesores y científicos. Se mantiene que el aprendizaje de la metodología científica sirve, en primer lugar, para formar el espíritu crítico del alumnado y, en segundo lugar, para dotarle de herramientas que le permitan en su futuro profesional actuar de manera racional y sistemática, contribuyendo, además, a ampliar las bases científicas de la Biblioteconomía y Documentación. A continuación se traza, en una breve panorámica histórica, el surgimiento y la evolución de la enseñanza de la metodología científica en las Escuelas y Facultades de Biblioteconomía y Documentación. Introducida en las Escuelas norteamericanas en los años 30, la enseñanza de métodos de investigación se ha convertido en la actualidad, de hecho, en una asignatura de importancia creciente en los planes de estudios. De la misma opinión son las asociaciones profesionales que consideran a esta materia como troncal. Esta misma calificación ha recibido en España, donde es de obligada impartición en la Licenciatura en Documentación
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Linero Segrera, Itali Marcelly
2012-01-01
La reconstrucción y restauración de la función esquelética continúa siendo un reto en el campo de la cirugía maxilofacial y la ortopedia. Una alternativa o terapia coadyudante a los tratamientos convencionales es la ingeniería de tejidos que surge como una posibilidad prometedora para la regeneración del tejido óseo. Con el fin de crear un modelo para la aplicación clínica de las células madre mesenquimales derivadas de tejido adiposo humano (Ad-MSCs) desarrollamos una matriz tridimensi...
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Souza, F.M.B. de; Carvalho, L.F.V. de; Alencar, M.G de; Boaventura, J.S. [Universidade Federal da Bahia (DFQ/UFBA), Salvador, BA (Brazil). Dept de Fisico-Quimica. Grupo de energia e Ciencias dos Materiais], e-mail: bventura@ufba.br
2008-07-01
The most promising technology for generating electric power, with reduced environmental impact, is the fuel cell. This technology is virtually non-polluting and the fuel supplies can be renewable. Therefore is necessary to study the technique of preparing the entire anode / electrolyte / cathode to optimize its operation. There are still major challenges to making the SOFC economically viable. The key is the improvement of manufacturing of its components and use of materials that can simultaneously reduce costs and reduce the temperature of operation. Among the properties of the cell, was shown the dependence of the efficiency of the device on the properties of the electrolyte, particularly its thickness. The mixture of YSZ with GDC in the composition of the anode and electrolyte aims to obtain a material with greater ionic conductivity. After sintering the cell was characterized by scanning electron microscopy (SEM). (author)
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Energy Technology Data Exchange (ETDEWEB)
Gandia, J. J.; Carabe, J.; Fabero, F.; Jimenez, R.; Rivero, J. M. [Ciemat, Madrid (Spain)
2000-07-01
The present status of amorphous-silicon-solar-cell research and development at CIEMAT requires the possibility to characterise the devices prepared from the point of view of their stability against sunlight exposure. Therefore a set of tools providing such a capacity has been developed. Together with an introduction to photovoltaic applications of amorphous silicon and to the photodegradation problem, the present work describes the process of setting up these tools. An indoor controlled-photodegradation facility has been designed and built, and a procedure has been developed for the measurement of J-V characteristics in well established conditions. This method is suitable for a kinds of solar cells, even for those for which no model is still available. The photodegradation and characterisation of some cells has allowed to validate both the new testing facility and method. (Author) 14 refs.
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CARCINOMA ODONTOGÉNICO DE CELULAS CLARAS. ESTUDIO CLÍNICO, RADIOLÓGICO Y PATOLÓGICO DE UN CASO.
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Rosaura Rodríguez Flores
2004-01-01
Full Text Available Los tumores odontogénicos (TO son un grupo complejo y poco frecuente de neoplasias con características clínicas, radiológicas, histopatológicas y evolución muy variables. El Carcinoma odontogénico de células claras (COCC es una neoplasia maligna, de comportamiento agresivo variable que se presenta en maxilares. Histológicamente se constituye de nidos de células, frecuentemente de citoplasma claro, rico en glucógeno, rodeadas por bandas de colágena. Pertenece al grupo de los tumores odontogénicos epiteliales malignos. Se presenta el caso de un hombre de 57 años con un tumor en hueso y seno maxilar izquierdo, sometido a hemimaxilectomía subtotal izquierda. Los estudios de imagen demostraron una lesión destructiva mixta en maxilar y seno maxilar izquierdo y la histología reveló la imagen clásica de COCC y la inmunohistoquímica mostró inmunoreactividad para Queratina AE1/AE3, EMA y S-100 (focal. Se demostró abudante glucógeno mediante la reacción de PAS en el citoplasma de las células neoplásicas. El paciente ha tenido seguimiento por 5 años y está asintomático después de la cirugía sin tratamiento complementario con radioterapia.
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Ricardo Julian Cabezas-Perez
2011-01-01
Full Text Available Son conocidas las propiedades del factor de crecimiento similar a la insulina IGF-II y de la hormona Gonadotropina Coriónica (hCG en la implantación y migración trofoblástica, sin embargo los mecanismos a través de los cuales ejercen sus efectos no han sido identificados. El objetivo de este estudio fue establecer la interacción potencial entre los efectos funcionales de hCG y el IGF-II en la regulación de la proliferación, migración e invasión trofoblástica. Utilizando la línea celular HTR-8/SVneo de trofoblasto extravelloso se pudo demostrar que tanto IGF-II como hCG estimulan la proliferación y migración celular sin observarse efectos aditivos en sus acciones, lo cual es indicativo independencia de sus mecanismos. En contraste, la capacidad invasiva del trofoblasto fue regulada por IGF-II y hCG, dando como resultado efectos aditivos o un potencial sinergismo entre las dos hormonas. En conclusión, nuestros resultados muestran la existencia de interacciones entre las acciones biológicas de IGF-II y hCG en la regulación de la capacidad invasiva de células trofoblásticas y contribuyen al entendimiento de la biología del trofoblasto y de su malignización.
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Energy Technology Data Exchange (ETDEWEB)
Oliveira-Silva, M.A.; Linardi, M.; Saliba-Silva, A.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio
2010-07-01
Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The membrane electrolysis has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with non-carbogenic causing no harm by producing gases deleterious to the environment. (author)
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Abraham Farias F
2007-04-01
Full Text Available Este trabajo trata sobre la integración de una célula flexible de mecanizado de tipo docente, compuesta por una fresadora didáctica CNC, marca Denford, un brazo robótico articulado de seis ejes, modelo Scorbot -ER Vplus y un riel deslizante; todos pertenecientes al Laboratorio de Manufactura Integrada por Computador, de la Escuela de Ingeniería Mecánica de la Universidad de Talca. Las tareas que realiza esta célula flexible son controladas por un PC director a través de un programa, utilizando el software y el propio control del robot y su objetivo es realizar el ciclo de carga y descarga de un trozo de material de 65×65×40 mm. (madera y su posterior mecanización. El problema de comunicación entre los equipos involucrados y la fresadora CNC fue resuelto en cuanto su diseño "stand alone" no contemplaba la integración con otros equipos. Por otro lado, se agregaron algunos sistemas electroneumáticos para que la operación fuera automática, como los de sujeción de piezas y la apertura y cierre de puertas. Con esta célula flexible de mecanizado de tipo docente, la facultad de Ingeniería cuenta con una plataforma básica, a la que se puede adicionar otras funciones, como por ejemplo, dotarla de un sistema automático de alimentación de piezas, de un sistema de visión digital para dar más autonomía al robot, incorporar un torno CNC y generar un programa para administrar las órdenes de trabajo.This paper describes the integration of an educational flexible manufacturing cell, consisting of a Denford CNC mill with six axes, and a Scorbot - ER Vplus robotic arm that slides along a rail. This equipment is located at the Computer Integrated Manufacture Laboratory, at the School of Mechanical Engineering at Universidad de Talca. The flexible cell is controlled by software in a PC that interacts with the software in the robotic arm. The specific tasks described in this paper are loading and unloading a wooden piece (640×65×40 and to mechanizing the piece. One difficulty solved in this work was the potential communication problem between the control equipment CNC mill, since the original, stand-alone design did not admit integration with other controllers. In addition, electro-pneumatic devices were added to permit automatic operation of the system in situations such as gripping the piece and opening the mill door. This basic platform gives the possibility of adding new functions and equipment, such as automatic loading of work pieces, digital reading systems, a CNC lathe and a work order information system.
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Energy Technology Data Exchange (ETDEWEB)
Soares, Sibelle F.C.X.; Melo, Dulce M.A.; Pimentel, Patricia M.; Melo, Marcus A. Freitas; Martinelli, Daniele M.H. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Quimica]. E-mail: sibelle.cunha@gmail
2008-07-01
This work aims to study on the obtaining powders of lanthanum manganite oxides with partial substitution of La with strontium at 20% for the application as a cathode for solid oxide fuel cell, through a route of synthesis that are similar to the Pechini method, in which gelatin replaces the ethylene glycol as polymerization agent. The method highlights itself due to its simplicity, low cost and capability to obtain crystalline powders with the high purity and good stoichiometric control. The perovskite obtained were characterized by thermogravimetric analysis, X ray diffraction, electronic scanning microscopy and the superficial area by BET method. The deposition of the perovskite on electrolyte/anode system was done through the spin coating technique. The methodology used for the perovskite synthesis was very efficient, considering a monophasic material was obtained and with characteristics that were proper to the application as electrode to solid oxide fuel cells. (author)
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Laura Rayón Rumayor
2011-03-01
Full Text Available Fruto de una propuesta de innovación, financiada por el Vicerrectorado de Comunicación y Planificación de la UAH en el curso 2007/08, surge la propuesta que presentamos en este documento, tras tres años de aplicación en la Licenciatura de psicopedagogía, en una asignatura troncal. Se han puesto en marcha tres estrategias formativas vinculadas a la creación y gestión del conocimiento por parte del alumnado de un modo cooperativo, quien además individualmente tiene la posibilidad de autorregular su aprendizaje. A través de una estructura cooperativa en el aula, vertebrada en torno a tres estrategias fundamentales: el relato fotográfico, las historias de vida y el diario personal de aprendizaje, vamos configurando un modelo formativo a lo largo de tres cursos académicos que compagina la cooperación con la autonomía y autorregulación del propio aprendizaje, así como la alfabetización multimodal de los estudiantes, quienes desempeñan un rol activo en la creación y gestión del conocimiento mediante la utilización de la fotografía para comunicar las ideas y el conocimiento que van adquiriendo. En el trabajo profundizamos en la estrategia que denominamos “relato fotográfico”, que se ha revelado como una estrategia útil para que el alumnado cree y gestione el conocimiento y lo pueda compartir con el resto de sus compañeros; productos que tienen como soporte los blogs grupales como espacio comunicativo entre los estudiantes.
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Energy Technology Data Exchange (ETDEWEB)
Acevedo, Luis Evelio Garcia; Oliveira, Amir Antonio Martins [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica], e-mail: evelio@labcet.ufsc.br, e-mail: amirol@emc.ufsc.br
2006-07-01
Here we present a thermodynamic and chemical kinetic analysis of the methane steam reforming for production of 5 kw of electrical power in a PEM fuel cell. The equilibrium analysis is based on the method of element potentials to find the state of minimum Gibbs free energy for the system and provides the equilibrium concentration of the reforming products. The objective of this analysis is to obtain the range of reforming temperature, pressure and steam-methane molar ratio that results in maximum hydrogen production subjected to low carbon monoxide production and negligible coke formation. The thermal analysis provides the heat transfer rates associated with the individual processes of steam production, gas-phase superheating and reforming necessary to produce 5 kw of electrical power in a PEM fuel cell and allows for the calculation of thermal efficiencies. Then, the chemical reaction pathways for hydrogen production in steam reforming are discussed and the available chemical, adsorption and equilibrium constants are analyzed in terms of thermodynamic consistency. This analysis provides the framework for the reactor sizing and for establishing the adequate operation conditions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Machado, Isabela M.M.; Gomes, Ana C.; Pessan, Luiz A. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Engenharia de Materiais], e-mail: isabelamuglia@gmail.com; Paranhos, Caio [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica
2011-07-01
Fuel cells based on ion conducting polymer membranes offer an alternative for the conventional energetic matrices. Among many advantages of this system, we can mention the reduction on the emission of pollutants, high efficiency and simplicity. This work presents the modification of polycarbonate by sulfonation reaction using acetyl sulfate, in order to increase the conductor ionic character of the membranes used as electrolytes for hydrogen fuel cells. The sulfonated polycarbonate membranes were obtained by casting and then characterized by Fourier transform infrared spectroscopy, water vapor transmission, differential scanning calorimetry, thermogravimetric analysis and viscosimetry. (author)
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Gary E. Rodrick
1981-09-01
Full Text Available The specific activities of acid phosphatase, alkaline phosphatase, β-glucuronidase, lysozymes, glutamate-oxalacetate transaminase and glutamate-pyruvate transaminate were determined in the head-foot and digestive gland of Brazilian Biomphalaria glabrata (Touros, B. tenagophila (Caçapava and B. straminea (Monsenhor Gil. All six enzymes were detected inthe 3000g supernatant. Both cytoplasmic enzymes, glutamate-oxalacetate and glutamate-pyruvate transaminase exhibited the highest specific activities. In the case of the four hydrolytic enzymes assayed, β-glucuronidase exhibited the highest specific activity while lysozyme showed the lowest activity. All six enzymes are thought to be produced by cells within the head-foot and digestive gland of B. glabrata, B. tenagophila and B. straminea.Foram determinadas, na massa cefalopedal e na glândula digestiva de Biomphalaria glabrata de Touros (Rio Grande do Norte B. tenagophila de Cacapava (Sao Paulo e B. straminea de Monsenhor Gil (Piauí, as atividades específicas das seguintes enzimas: fosfatase acida, fosfatase alcalina, beta-glucuronidase, lisozima, transaminase glutâmico-oxalacetica e transaminase glutâmico-piruvica. As seis enzimas referidas foram detectadas no sobrenadante a 3000g. Ambas as enzimas citoplasmaticas - transaminases glutamico-oxalacetica e glutamico-piruvica - mostraram as atividades específicas mais altas. No caso das quatro enzimas hidrolíticas, a beta-glucuronidase revelou a mais alta atividade específica, enquanto a lisozima revelou a mais baixa. E admitido que todas as seis enzimas sao produzidas por celulas presentes na massa cefalopedal e na glândula digestiva das tres especies de moluscos examinadas.
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Patricia de Azambuja
1984-12-01
Full Text Available Precocene II, added to the meal of fourth-instar larvae of Rhodnius prolixus (25 mug/ml of blood, induced an in crease in the duration of the molting cycle. This effect was related to the decrease of both the nuclear area of the prothoracic gland cells and the mitotic activity in epidermal cellS. juvenile hormone analogue applied topically (60 mug/insect together with Precocene II treatment avoided atrophy of the prothoracic glands and induced a higher number of epidermal mitosis accelerating the time of subsequent ecdysis. A possible relationship between juvenile hormone and production of ecdysone is discussed.Adicionado ao sangue alimentar na dose de 25 mug/ml o precoceno II causou um aumento no período de intermuda em ninfas de 4o. estadio de Rhodnius prolixus. Este atraso da muda foi relacionado com a diminuição da área dos núcleos das celulas das glandulas protoracicas e com a queda da atividade mitotica das células da epiderme do inseto. Um análogo de hormônio juvenil aplicado topicamente (60 mug/inseto junto com o tratamento oral com precoceno II preveniu a atrofia das glândulas protorácicas e induziu um aumento no número de mitoses nas células da epiderme, diminuindo o período de intermuda nestes insetos.A possivel relação entre a ação do hormônio juvenil e a producao de ecdisona pelas glândulas protorácicas e discutida.
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Metaplasia mieloide do baço na Ancilostomose
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W. O. Cruz
1934-06-01
Full Text Available Pesquizamos, no figado e baço de dez casos puros de ancilostomose, elementos hemocitopoieticos; verificamos o peso do baço em 23 casos de individuos com idades compreendidas entre 3 e 60 anos; não encontramos, em nenhum caso, celulas hemoformadoras no figado. Em sete casos, encontramos, no baço, elementos da série vermelha em adiantado estado de evolução (eritroblastos ortocromaticos de nucleo picnotico. Em alguns destes casos observamos megacariocitos e numerosos mielocitos eosinofilos. Os tres casos que não apresentavam metaplasia mieloide no baço, eram os de individuos acima de 50 anos de idade. Entretanto, em outro caso de um individuo com 59 anos esta metaplasia foi verificada. Em individuos acima de 20 anos, o peso médio do baço, em nove casos, mostrou-se igual ao peso normal. Em 14 casos, compreendidos entre 3 e 14 anos, o peso deste orgão foi sempre sensivelmente mais elevado que nos normais de idade correspondente. Estes resultados sugerem a possibilidade de ser a metaplasia mieloide responsavel pelos aumentos de pezo nos baços de individuos jovens, vitimados pela anemia ancilostomica. A notavel proliferação dos eritroblastos ortocromaticos mostra que o grão e a rapidez da regeneração sanguinea, após a administração de ferro, são devidos, essencialmente, á grande quantidade de hemoglobina já preformada no baço e na medula ossea dos organismos ancilostomados.
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Energy Technology Data Exchange (ETDEWEB)
Biagini, C.; Paleani Vettori, P. G.; Zito Bignami, R. [Istituto di Radiologia dell' Universita and Comitato Nazionale per l' Energia Nucleare, Rome (Italy)
1962-02-15
mamiferos por rayos X de 150 kVp y por electrones de 15 MeV emitidos por un betatron. En la memoria se exponen los resultados de un estudio autorradiografico sobre el comportamiento de diferentes clases de celulas del timo de los ratones, en el que se ha utilizado timidina tritiada como precursor del acido desoxirribonucleico. Los datos se relacionan con las modificaciones de la distribucion de tamanos en la poblacion celular y con el peso del organo. Despues de la irradiacion, aumenta la razon macrocitos/microcitos y la incorporacion de timidina tritiada disminuye tanto en los linfocitos grandes como en los pequenos. Durante la fase en que los efectos se manifiestan con mayor intensidad, no se observan diferencias significativas entre los rayos X y los electrones en cuanto al tamano de las celulas o la marcacion de los macrocitos. En la marcacion de los microcitos se advierte una variacion relativa que concuerda con los datos referentes al peso del organo y que puede estar relacionada con el valor de la EBR de los electrones rapidos. En la fase de restauracion, las celulas menos diferenciadas proliferan activamente, pero el porcentaje de linfocitos maduros sigue siendo bajo. Despues de la exposicion a electrones de 15 MeV, la actividad de proliferacion de los macrocitos aumenta, segun la curva de la atrofia del timo en funcion del tiempo. A juzgar por estos resultados, la capacidad de regeneracion parece estar relacionada con la gravedad de la lesion de las celulas primitivas; para una dosis determinada, esta ultima es mayor cuando la irradiacion se efectua con rayos X que cuando se realiza con electrones. (author) [Russian] Mehanizm vosstanovlenija posle ostrogo radiacionnogo porazhenija mozhet byt' izuchen pri pomoshhi ispol'- zovanija radiacii dvuh vidov s nebol'shoj raznicej v zhestkoj otnositel'noj biologicheskoj jeffektivnosti, no so znachitel'nymi rashozhdenijami rezul'tatov v faze vosstanovlenija. Na osnovanii nabljudenij pri predydushhih onpytah zto usldovie
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Energy Technology Data Exchange (ETDEWEB)
Belchior, P.M.; Forte, M.M.C. [UFRGS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Serafin, R.; Fusiger, V.; Carpenter, D. [FURB - Fundacao Universidade Regional de Blumenau, SC (Brazil)
2010-07-01
This experiment aimed to verify the influence due to the variation of the compacting force applied to a DEFC. According to the tests, as the increase of cell compacting, the performance improves significantly. According applied tests, when the high electrical conductivity components are used, small differences of the cell compacting can generate a large difference on the total ohmic resistance. Through the tests one can conclude that with the increase of cell compacting, the contact probably increase among the distribution of reagents and the diffuser layer, improving the cell performance. (author)
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González Méndez, Laura
2014-01-01
Tesis doctoral inédita, leída en Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 21/03/2014 En los últimos años se ha identificado a la serotonina como un regulador crítico de la masa ósea, regulando tanto directa como indirectamente la actividad de las células responsables del proceso de remodelación ósea, osteoclastos y osteoblastos. El presente trabajo muestra que las MSCs aisladas de la médula ósea humana, células precursoras ...
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Directory of Open Access Journals (Sweden)
M.ª del Carmen Jiménez Díaz
2011-03-01
Full Text Available El envejecimiento poblacional ha condicionado que la mayor parte de la actividad profesional de numerosos titulados de diferentes carreras se realice en personas ancianas. En su vertiente no intencional, el abandono del anciano como tipo de maltrato se puede deber a un conocimiento inadecuado (tal y como se define la impericia profesional. Por ello, la etapa de formación de la carrera reviste gran importancia en el cumplimiento de la misión universitaria. Así, todos los profesionales que desarrollen su actividad profesional con mayores deben tener conocimientos en gerontología que les permitan obtener, en cada momento, los mejores resultados posibles. Metodología: análisis descriptivo de los planes de estudio de las carreras de Enfermería, Medicina, Fisioterapia, Trabajo Social, Terapia Ocupacional y Ciencias de la Actividad Física y el Deporte. Conclusiones: excepto en Enfermería y Terapia Ocupacional, el resto de titulaciones universitarias no ofertan asignaturas troncales relacionadas con el envejecimiento.Population aging has conditioned most of the professional activity of many graduates of different degrees, to be conducted in older people. In its unintended side, abandoning the elderly, such as type of abuse, may be due to inadequate knowledge (defined as the professional skill, so the training stage of the race of great importance in meeting the university mission. Thus, all the professionals who develop their professional activity with older should have knowledge in gerontology to enable them to obtain at each moment the best possible results. Methodology: descriptive analysis of the curricula of degree programs in Nursing, Medicine, Physiotherapy, Social Work, Occupational Therapy and Science of Physical Activity and Sport. Conclusions: except in Nursing and Occupational Therapy, the other university degrees offered no core subjects related to aging.
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Introducción a la Matemática Económico-Empresarial: balance de una materia de libre elección
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R. Sala Garrido
2000-01-01
Full Text Available Desde el curso 1997/98, y debido a la diferente formación matemática con la que los estudiantes acceden a las licenciaturas de Economía y Administración y Dirección de Empresas y a la diplomatura en Ciencias Empresariales según sus estudios previos, la Universitat de València ofrece un módulo teórico-práctico de libre elección llamado Introducción a las Matemáticas Económico-Empresariales. La génesis, objetivos y estructura de dicho módulo fueron presentados por los autores en las VI Jornadas de ASEPUMA (Santiago, 1998, junto con unos primeros resultados basados en los datos disponibles en aquellos momentos: tan sólo los de la primera convocatoria. Este primer estudio sobre datos cruzados apuntaba ya la efectividad del módulo sobre el resto de asignaturas troncales de matemáticas y, en consecuencia, sobre el resto de las materias que apoyan su desarrollo y resultados sobre las matemáticas. En la actualidad, con datos históricos suficientes, presentamos la ratificación de los resultados anteriores. Su efectividad ha sido tal que en la "contrarreforma" emprendida por la Universidad el módulo ha pasado de ser un módulo de libre elección a tener carácter optativo y de ser intensivo a tener una duración semestral. Este hecho precisa una reflexión acerca de su tamaño y enfoque. Sin embargo, este módulo ha seguido la dinámica del resto y el porcentaje de aprobados ha descendido en cada convocatoria. En este trabajo analizamos las posibles causas de este hecho y planteamos algunas modificaciones en el temario debidas a los cambios introducidos.
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DAÑO VELLOSO HIPOXICO EXTENSO EN VELLOSIDAD PLACENTARIA INFECTADA POR PLASMODIUM VIVAX.
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Olivar C. Castejon
2011-01-01
Full Text Available Objetivo: El propósito de este estudio de caso fue el determinar el daño velloso hipóxico extenso en una población de vellosidades obtenida de una placenta infectada por Plasmodium vivax y tratada con cloroquina cuantificando el daño en relación a otra población normal no infectada. Métodos: Un protocolo de observación se aplicó a la placenta infectada conteniendo las variables que definen el daño como la presencia de nódulos sincitiales, hipovascularidad vellosa y vellosidades fibróticas o avasculares cuyos porcentajes en la placenta estudio y control fueron medidos estadísticamente para estimar las diferencias significativas. Diez láminas teñidas con hematoxilina y eosina por cada placenta fueron empleadas determinándose el porcentaje de cada variable en 100 vellosidades en ambas placentas. Resultados: La placenta con P.vivax presentó entre un 29 y 58 % de nódulos sincitiales mientras que el control 3 y 24%. La fibrosis estromal entre 12 y 49%;la control entre 1 y 7%. La hipovascularidad entre 49 y 84%; la control entre 7 y 18%. Trombosis intervellosa, oclusión de la luz de vasos troncales,infartos y corangiosis se observaron en la infectada y no en el control. Conclusiones: Estos resultados sugieren un daño velloso hipóxico extenso en las vellosidades infectadas mientras que las del control permanecen normóxicas. Dicho daño pudiera impedir el suministro de gases y nutrientes que estimularía a nivel fetal la restricción del crecimiento intrauterino con la subsiguiente pérdida de peso fetal.
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Josefa Larrán López
Full Text Available La importancia de realizar un diagnóstico sobre la situación inicial de los alumnos que comienzan un nuevo curso es de sobras conocida. Los resultados del proceso de enseñanza-aprendizaje dependen en gran medida del estado inicial de preparación y motivaciones de los alumnos. Por tanto, la identificación de factores que se relacionen con el rendimiento académico es un tema a tener en cuenta en el proceso de mejora de la calidad de la enseñanza universitaria. En el presente trabajo presentamos datos obtenidos a partir de la evaluación inicial realizada a los alumnos de la asignatura troncal Biología Celular y Tisular Humana de primer curso de la Diplomatura en Fisioterapia. Como instrumento utilizamos un cuestionario de respuesta abierta que nos proporciona información sobre distintas variables como: sexo, modalidad de acceso a la Universidad, motivaciones, aspiraciones, conocimientos previos relacionados con la asignatura, etc. Presentamos, igualmente, la calificación final obtenida por los alumnos (evaluación sumativa. Realizamos un análisis descriptivo de las variables iniciales, relacionándolas entre sí y con las calificaciones finales con objeto de identificar factores indicadores del rendimiento académico. Entre los resultados obtenidos observamos que los conocimientos previos relacionados con la asignatura son, en general, insuficientes y/o confusos, observándose una mejor preparación previa en los alumnos procedentes de COU/Bachillerato con respecto a los de Formación Profesional. Entre las variables analizadas son estos conocimientos previos los que muestran una relación estadísticamente significativa y directamente proporcional con las calificaciones finales.
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Cambios en las estructuras de los hogares Rurales. Formas de adaptación y resiliencia
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Camarero Rioja, Luis
2014-08-01
Full Text Available This paper examines the capacity of household structures to respond to environmental conditions. First, it looks at the relationship between demographic sustainability and the resilience of rural households. Afterwards, it examines basic mechanisms of adaptation between household structures and the socioeconomic environment based on the theories of Chayanov and Le Play. The empirical research, carried out in rural Spain, found that household structures first underwent a process of modernization, followed more recently by certain diversification. Within this process, what stands out is the number of adult children that extend the period of cohabitation with their parents, constituting similar strategies to those traditionally employed by stem families. In the current context of rural areas, household structures have shown resilience in the face of socioeconomic changes.Este artículo trata sobre la capacidad de las estructuras de hogar para responder a las condiciones ambientales. En primer lugar, se expone la relación entre sostenibilidad demográfica y resiliencia de los hogares en las áreas rurales. A continuación, se presentan los mecanismos básicos de la adaptación entre las estructuras de hogar y entorno socioeconómico a través de las teorías de Chayánov y Le Play. Se analiza empíricamente la España rural, donde se constata una etapa de modernización de las estructuras de hogar, seguida más recientemente de cierta diversificación. Dentro de este proceso, destaca el número de hijos que alargan el periodo de convivencia con sus padres, constituyendo estrategias similares a las tradicionalmente empleadas por las familias troncales. En el actual contexto de las áreas rurales, las estructuras de hogar muestran su condición resiliente ante los cambios socioeconómicos.
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Energy Technology Data Exchange (ETDEWEB)
Miyake, Raphael Guardini; Bazzo, Edson [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Combustao e Engenharia de Sistemas Termicos], e-mail: miyake@labcet.ufsc.br, e-mail: ebazzo@emc.ufsc.br
2006-07-01
Fuel cells have been considered a promising alternative for electric energy generation. In order to contribute with the development of this technology, a PEM fuel cell was installed and new experiments were carried out at LabCET (Laboratory of Combustion and Thermal System Engineering). Previous results have shown polarization curves identifying the need of rigorous controlling of humidification temperature of the fuel cell. In this paper, new results were carried out considering the use of a fan connected to the fuel cell and possible degradation in the electrolyte, after a relative long time operation. New polarization curves were plotted for comparison with previous results. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silva, Ennio Peres da; Apolinario, Fernando Rezende; Furlan, Andre Luis [Universidade Estadual de Campinas (IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Lab. de Hidrogenio], Emails: lh2ennio@ifi.unicamp.br, rezende@ifi.unicamp.br; Souza, Rubem Cesar Rodrigues [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Centro de Desenvolvimento Energetico Amazonico], Email: rubem_souza@yahoo.com.br; Pinto, Adailton de Souza [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Brasilia, DF (Brazil)], Email: adailton@eln.gov.br
2006-07-01
This article presents a project whose main objective is to analyze the technical feasibility of using a system based on the production of hydrogen (H{sub 2}) for storing the energy generated for photovoltaic systems. The work involves the design, physical implementation and the performance evaluation of a system for hydrogen electrolytic generation with solar-photovoltaic energy, the treatment os gas, its storage and it use in fuel cell systems. This work will be performed in cooperation between researchers from the Laboratorio de Hidrogenio (LH2) of the UNICAMP and of the Centro de Desenvolvimento Energetico Amazonico (CDEAM) of the UFAM, and is financing by ELETRONORTE.
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Energy Technology Data Exchange (ETDEWEB)
Marrero, Jacqueline C.; Gomes, Ailton de S.; Filho, Jose C.D., E-mail: jacquecosta@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Hui, Wang S. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil); Oliveira, Vivianna S. de [Escola Tecnica Rezende-Rammel, Rio de Janeiro, RJ (Brazil)
2015-07-01
Polymeric membranes were developed using a SPEEK polymer matrix (sulphonated poly (ether ether ketone)), containing hygroscopic particles of zirconia (Zr) (incorporated by sol-gel method), for use as electrolyte membranes in fuel cells. SPEEK with different sulfonation degrees were used: 63 and 86%. The thermal analysis (TGA and DSC) was carried out to characterize the membranes and electrochemical impedance spectroscopy (EIS) was carried out to evaluating the proton conductivity of the membranes. Additional analysis were underway in order to characterize these membranes, which include: X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in order to evaluate the influence of zirconia and sulfonation degree on the properties of the membranes. (author)
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Directory of Open Access Journals (Sweden)
Lucila Arcay
1986-06-01
Full Text Available Se hace un estudio de la interacción de promastigotes de Leishmania donovani con células de exudado peritoneal de ratón (c e p mediante la influencia de la quimotripsina. La adhesión de los promastigotes a las c e p fue terminal y marginal, y en observaciones hechas a partir de los 10 minutos de enfrentamiento, esta adhesión fue nula hasta los 30 minutos en el grupo tratado, y sólo a las das horas hubo un pequeño incremento (2.4% con respecto al control. Se observa marcada disminución en todos los parámetro medidos, tales como enlace, penetración, multiplicación intracelular, división de formas flageladas, en el grupo tratado. La quimotripsina favorece la formación de formas intermedias flageladas, heciendose el parásito piriforme y esférico, apareciendo una forma aberrante de extremo anterior cilindrico que semeja a una forma coanoflagelada. Se sospecha que la enzima reduce efectivamente fragmentos proteicos o péptidos, los cuales pueden haber sido tan pequeños como para esconder a otros ligandos relacionados con la adhesión macrófago-parásito.
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Unconventional cells of TiO2 doped with erbium; Celulas nao convencionais de TiO2 dopado com erbio
Energy Technology Data Exchange (ETDEWEB)
Ribeiro, P.C.; Campos, R.D.; Oliveira, A.S.; Wellen, R., E-mail: pollyana@cear.ufpb.edu.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Diniz, V.C.S.; Costa, A.C.F.M. da [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais
2016-07-01
The technology used in TiO{sub 2} solar cells is in constant improvement, new configurations have been developed, aiming practicality and leading to efficiency increase of photovoltaic devices. This paper proposes a new technology for the production of solar cells in order to investigate a better utilization of solar spectrum of TiO2 doped with erbium (Er{sup 3+}), proven by energetic conversion. The Ti{sub 0,9}Er{sub 0,1}O2 system was obtained by Pechini method. Nanoparticles have a crystallite size 65.30 nm and surface area 118.48 m{sup 2}/g. These characteristics are essential for the formation of the film to be deposited on the conductive glass substrate constituting the cell's photoelectrode. The other side of the cell is the platinum counter electrode. The cell will have the faces sealed by a thermoplastic and, finally the electrolyte will be inserted, then they will be electrically evaluated through energy efficiency and confronted with the literature data base. (author)
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Directory of Open Access Journals (Sweden)
Geranina Escovar V.
1982-06-01
Full Text Available Mediante el uso de los métodos de peroxidasa anti-peroxidasa e inmunofluorescencia aplicada a tejidos desparafinados y tratados con tripsina, se estudiaron inmunocitoquímicamente un grupo de placentas y tumores malignos. Al utilizar anticuerpos anti-GCH, la hormona gonadotropina coriónica humana (GCH fue localizada en células del sincitiotrofoblasto de placentas de diferentes estados de desarrollo, se encontró, además, que las c6lulas de Langhan's y del citotrofoblasto fueron negativas a la inmuno-reacción. La mayoría de los tumores estudiados fueron encontrados positivos al aplicar los métodos mencionados. Se postula que la inmunosupresión selectiva del huésped por tumores y la inmunosupresión selectiva de tejidos maternos por tejidos fetales. podría estar mediada por la hormona gonadotropina coriónica.
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Juares Ednaldo Romero Bianco
2006-01-01
Resumo: Durante o período peri-implantacional na gestação de humanos e roedores, ocorre no estroma da mucosa uterina um conjunto de fenômenos que envolvem modificações dos componentes celulares e da matriz extracelular. Este conjunto de modificações é conhecido como decidualização ou reação decidual. Concomitante a este processo ocorre a migração de leucócitos provenientes de órgão hematopoéticos para este estroma. Dentre estes leucócitos predominam as subpopulações de linfócitos denominados ...
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Alexandre Guass Junior
1995-01-01
Resumo: Este trabalho teve como objetivo o desenvolvimento de um conjunto de processos de baixo custo para fabricação de células solares. As células solares foram fabricadas utilizando lâminas de silício monocristalino, com orientação cristalografica e resistividade típica de 4.1 à 9.0 ohm.cm, tipo p dopadas com boro. Ajunção n-p foi obtida por difusão usando papéis dopantes. Estes papéis são de dois tipos, os que possuem boro e os com fósforo.A montagem de um conjunto de lâminas de s...
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Fibroma odontogenico en maxilar inferior. Apropósito de un caso
Directory of Open Access Journals (Sweden)
Gustavo Guzmán
2013-10-01
Full Text Available Title: Mandibular odontogenic fibroma. A case report.Resumen: Los tumores benignos son neoplasias que se pueden presentar en cualquier parte de la cavidad oral estos pueden ulcerarse, sangrar o interferir con la masticacion o con la adhesion de protesis dentales, tambien presentan un desarrollo lento, una superficie mucosa conservada y compresion de estructuras vecinas. Los fibromas odontogenicos son tumores benigno poco frecuente caracterizado por tejido fibroso con celulas de tejido conectivo, este se puede presentar en cualquier etapa de la vida, no tiene predileccion de sexo y se da mas en la mandibula que en los maxilares. El objetivo de este artículo es describir un caso clínico de este tumor, hacer una breve revisión de la literatura, analizar sus características clínicas e histológicas y la actitud terapéutica a tomar.(DUAZARY 2012 No.2, 190 - 195AbstractBenign tumors are growths that can occur in any part of the oral cavity they can ulcerate, bleed, or interfere with chewing or the adhesion of dental prostheses, also show a slow development, a preserved mucosal surface and compression of adjacent structures. Odontogenic fibroma is a fairly common tumor tissue characterized by fibrous connective tissue cells, this can occur at any stage of life, has no sex predilection an occurs more in the mandible than the maxilla. The aim of this paper is to describe a case of this tumor, a brief review of the literature, analyze their clinical and histological features and therapeutic approach to take.Keywords: Ossifying fibroma; benign neoplasms; fibromas; Jaw Neoplasms.
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Energy Technology Data Exchange (ETDEWEB)
Aguiar, Liz C.V. de; Almeida, Raquel D. de; Gomes, Ailton de S. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)], e-mail: lizcontino@ima.ufrj.br; Ramos Filho, Florencio G. de [Centro Universitario Estadual da Zona Oeste - UEZO, Rio de Janeiro, RJ (Brazil)
2011-07-01
Hybrids organic-inorganic membranes PVA-silica have been prepared using sol-gel process in situ with the objective of study the influence of inorganic particles incorporation on the water uptake, pervaporation and proton conductivity of PVA membranes. The silica was constituted of mercaptopropyltrimethoxysilane (MPTMS) with or without the mixture with the tetra ethoxysilane (TEOS). The hybrids membranes were oxidated to convert the -SH groups in -SO{sub 3}H groups, becoming them proton conducting. The hybrids membranes not oxidated showed lesser water uptake and pervaporated material, probably, due to the formation of crosslink that restricted the swell of the PVA membrane. The protonic conductivity of the hybrid membranes after the oxidation was up to 26 times bigger than of the membrane not oxidated. (author)
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Directory of Open Access Journals (Sweden)
Flavia Natercia da Silva Medeiros
2013-11-01
Full Text Available Noções de natureza desempenham um papel na cobertura midiática e nas percepções do público sobre as biotecnologias. Neste estudo, fez-se uma análise de discurso das ideias de natureza e natural usadas na cobertura jornalística brasileira da clonagem e das células-tronco. Nos discursos oponentes, as técnicas biotecnológicas foram postas fora da ordem natural e consideradas imorais. Nos discursos defensores, apareceu uma natureza indiferente ou cruel para com o destino humano, ou obstáculo a ser superado; por outro lado, a clonagem e as células-tronco embrionárias foram naturalizadas, e a ovelha Dolly foi antropomorfizada. As representações mitificantes ou transcendentes da natureza não incidem somente sobre as percepções públicas, têm implicações éticas e políticas.
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Energy Technology Data Exchange (ETDEWEB)
Furtado, Jose Geraldo de Melo; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: furtado@cepel.br; Codeceira Neto, Alcides [Companhia HidroEletrica do Sao Francisco (CHESF), Recife, PE (Brazil)
2008-07-01
This paper describes the electrochemical behavior of a proton exchange membrane fuel cell in function of temperature and time of operation. Different polarization phenomena are considered in the 30 to 70 deg C temperature range, as well as the degradation of electrochemical behavior of the fuel cell analyzed up to 1260 hours of operation. The results show that there is a tendency for the experimental values approaching the theoretical as it increases the temperature of the membrane electrolyte. The electrochemical behavior of the PEMFC studied proved to be less stable at 70 deg C. On the other hand, at 30 deg C the fuel cell performance proved to be considerably lower than at other temperatures. Also, it was found that in certain current ranges occurs greater overlay in potential-current curves, and in some cases reversing between these curves depending on the electric current required for the data obtained at 60 and 70 deg C, indicating, perhaps, that at 70 deg C the characteristics of the electrolyte are slightly inferior to those at 70 deg C, corresponding to an electrolyte degradation. Additionally, for the system studied, we found that the rate of variation of the potential difference in function of the temperature is quite high at the beginning of the operation process and tends to stabilize in a level of around 2,3-2,5 {mu}V per minute for times greater than 330 hours of operation. (author)
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Energy Technology Data Exchange (ETDEWEB)
Bambace, Luis Antonio Waack; Nishimori, Miriam; Ramos, Fernando Manuel [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)], e-mail: bambace@dem.inpe.br; Bastos Netto, Demetrio [Instituto Nacional de Pesquisas Espaciais (INPE), Cachoeira Paulista, SP (Brazil)
2004-07-01
This paper discusses a mathematical model for the chemical reactions and liquid phase flow processes occurring in a fuel cell cathode through non homogeneous catalysis carried by gold and Prussian Blue. The gold is applied inside the porous walls of micro-tubes, which may be obtained through several methods. The wall porosity ranging from 7 to 30% ensures gas exchange between the interior of a micro-tube and its exterior where gas flow takes place. The Prussian Blue consists of a thin porous layer located between the selective membrane and the micro-tube system, with void fraction in the 70 to 80% range. A porous electricity conducting carbide flux collector is placed between the tube system and the bipolar plates. The system return tubes possess a diameter much larger than one of the micro-tubes. The electric potential differences generated by the ionic currents in the system and its asymmetrical shape are used to generate electrocapillary flows, which are related with the surface tension changes with local potential. The hydrogen peroxide concentration and its transport to the Prussian Blue layer, and the oxygen transport inside the reactive tubular system are analyzed in this work. (author)
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Energy Technology Data Exchange (ETDEWEB)
Perez Borrego, Amparo [Facultad de Ciencias Medicas ' Enrique Cabrera' , La Habana (Cuba); Dominguez Rodriguez, Libia; Ilisastigui Ortueta, Zaida Teresa [Facultad de Estomatologia, La Habana (Cuba); Hernandez Ramirez, Porfirio [Instituto de Hematologia e Inmunologia, La Habana (Cuba)], E-mail: amparop.borrego@infomed.sld.cu
2009-07-01
The aggressive periodontitis might to provoke the tooth loss, of its function and to affect the patient's aesthetics. The techniques used for the lost bone regeneration, not always are successful and in occasions are very expensive. For years it is working in tissues regeneration by stem-cells implantation. Periodontium could be a potential for this task. This is a study of a female patient aged 26 with an apparent health status and aggressive periodontitis backgrounds treated from 10 years ago, seen in our service due to dental mobility producing mastication nuisances. At clinical examination we noted systemic chronic inflammation of gums, grade II and III dental mobility in incisives and molars teeth, 4-8 mm systemic periodontal sacs and furcation lesions in inferior molars. At radiographs advanced bone losses and a decrease of systemic bone density are noted. After written consent and the initial preparation, we carried out a periodontal flap in the 35 and 37 teeth zone, where the stem-cells concentrate was placed, in bone defects of superior molars (16-17) and previous radicular scraping and isolation, treatment consisted in stem-cells perfusion without flap. There were not postoperative side effects. At 7 days there was a normal coloration, at three months on noted at radiograph a bone neoformation, and at six months gum remained healthy, with a decrease of dental mobility in segment treated and in the evolutionary radiograph it was evidenced the formation and increase of density.
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Energy Technology Data Exchange (ETDEWEB)
Zamora Montes de Oca, Maria Jose
2012-07-01
The T1 renal cancer in adults is made known; incidence, characteristics and management. Renal cell carcinoma has been the most common malignancy of the kidney, percentage is close to three percent of solid tumors of adults. The treatments for this tumor are analyzed: open radical nephrectomy, laparoscopic radical nephrectomy, open partial nephrectomy and laparoscopic partial nephrectomy. Laparoscopic partial nephrectomy has represented an alternative option acceptable, safely and with good oncological and surgical outcomes for patients, as it is used to conserve nephrons and simultaneously to resect the tumor of a complete form promoting in the future the patient present a good renal function. Additionally, a adequate oncological control has reduced the risk of submit postoperative renal failure. An evolution of laparoscopic partial nephrectomy is presented determining the procedure for renal tumors in state T1 in the adults [Spanish] El cancer renal T1 en adultos es dado a conocer; su incidencia, caracteristicas y manejo. El carcinoma de celulas renales ha sido la malignidad mas comun de los rinones, su porcentaje se acerca al tres porciento de los tumores solidos de los adultos. Los tratamientos para combatir ese tumor son analizados: nefrectomia radical abierta, nefrectomia radical laparoscopica, nefrectomia parcial abierta y nefrectomia parcial laparoscopica. La nefrectonomia parcial laparoscopica ha representado una opcion alternativa aceptable, segura y con buenos resultados oncologicos y quirurgicos para los pacientes, ya que es utilizada para conservar nefronas y a la vez poder resecar el tumor de una forma completa promoviendo en el futuro que el paciente presente un buen funcionamiento renal. Ademas, un adecuado control oncologico ha reducido el riesgo de presentar insuficiencia renal postoperatoria. Una evolucion de la nefrectonomia parcial laparoscopica es presentada determinando el procedimiento para tumores renales en estado T1 en los adultos.
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Asymmetric electrooptic response in a nematic liquid crystal
Energy Technology Data Exchange (ETDEWEB)
Dascalu, Constanta [Politechnica University of Bucharest, Bucharest (Romania)
2001-06-01
An asymmetric electrooptic response in nematic liquid crystal (LC) has been obtained. The liquid crystal hybrid cell was made by using a standard configuration. One of the ITO (Indium Tin Oxide) electrodes was covered with a surfactant, which induces a homeotropic alignment. The second of the indium tin oxide electrodes was covered by a thin layer of photopolymer, which was previously mixed with an acid, which favours a process of release of protons. Such cations are responsible of electrochemical process in the LC leading to an asymmetric electrooptic response, which depend on the polarity of the applied electric field. This fact is due to an internal field, which change the effective voltage thresholds for the reorientation of the liquid crystal. During the anodic polarization, the optical switching is inhibited because the effective field decreases below the threshold value. On contrary for the opposite polarization the effective field is enough to determine a homeotropic alignment. [Spanish] Se ha obtenido una respuesta electro-optica asimetrica en cristales liquidos neumaticos. La celula hibrida de cristal liquido fue construida utilizando una configuracion estandar. Uno de los electrodos ITO fue cubierto con una pelicula delgada de material organico para inducir una alineacion homeotropa. El otro electrodo ITO fue cubierto con una pelicula delgada de fotopolimero anteriormente mezclada con un acido para favorecer la emision de protones. Estos cationes son responsables del proceso electroquimico en LC, conduciendo a una respuesta electro-optica asimetrica que depende de la polaridad del campo electrico aplicado. Este efecto es originado por un campo interno que cambia el umbral efectivo del voltaje para la reorientacion del cristal liquido. Durante la polarizacion anodica, la conmutacion optica se inhibe debido a que el campo efectivo disminuye abajo del valor del umbral. Por el contrario, para la polarizacion opuesta el campo efectivo es suficiente para
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Energy Technology Data Exchange (ETDEWEB)
Fiuza, R.P.; Souza, D.R. de; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: raigenis@gmail.com
2006-07-01
The PEMFC (Proton Exchange Membrane Fuel Cell), along the SOFC (Solid Oxide Fuel Cell), is the most important technology, among the various types of fuels cell. The PEMFC shows a large versatility of applications, both for stationary and mobile use. However the PEMFC presents high manufacture cost, directly impacting in the cost of the produced energy. This work contemplates the previews sulfonation of phtalic acid and its subsequent polymerization with glycerol, using as catalytic tin dibutyl-dilaurate. The obtained material has been characterized by DSC, TGA, FTIR, MEV, DRX and XRF. The gotten results indicated that phtalic acid was sulfonated and the increase of the sulfonation degree significantly increased the crystallinity of the sulfonated ftalico acid. Furthermore, the polymer produced from the sulfonated monomer presented adequate thermal resistance and a high content of conducting groups, necessary conditions for application as electrolyte in PEMFC. All these characteristics, particularly the low cost of the reagents and the ease of production process, make the sulfonated polyester membrane a promising candidate as fuel cell electrolyte. (author)
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Energy Technology Data Exchange (ETDEWEB)
Sousa, Iolanda; Pereira, Jose; Alcobia, Hernani [Net Plan Telecomunicacoes e Energia, Lisboa (Portugal); Pereirinha, Paulo [Instituto Politecnico de Coimbra (Portugal); Instituto para Engenharia de Sistemas e Computadores de Coimbra (Portugal)
2011-10-15
This paper presents a hybrid system that provides power to a remote and autonomously telecommunications station by means of electrical solar generators, wind and hydrogen fuel cell. In the absence of sufficient sun and wind, a bank of batteries and hydrogen produced on-site guarantee the power supply. The station can still be remote monitored and managed.
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Energy Technology Data Exchange (ETDEWEB)
Salgado, Jose Ricardo Cezar; Antolini, Ermete; Santos, Ana Maria dos; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica], e-mail: salgado@iqsc.usp.br
2004-07-01
Direct methanol fuel cells use platinum alloys as more efficient catalysts than platinum. In the case of binary alloys, the second metal affects several properties of platinum, like the interatomic distance, the electronic density and the capacity of forming oxygenated species at lower potentials. In this work, Pt-Ni catalysts supported on high surface area carbon (Pt-Ni/C) were prepared and characterized, and tested as catalysts in the anode and the cathode in direct methanol fuel cells. In both cases the performance of the material was better than that of Pt/C, and comparing the two situations it was better when the material was used in the cathode. The improved performance in the cathode was attributed to the nickel that forms a true alloy with platinum, while the better performance in the anode was attributed to the presence of nickel oxides. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silveira, Jose Luz; Leal, Elisangela Martins [UNESP, Guaratingueta, SP (Brazil). Escola de Engenharia. Dept. de Energia]. E-mails: joseluz@feg.unesp.br; elisange@feg.unesp.br
2000-07-01
In this paper, a methodology for the study of a molten carbonate fuel cell cogeneration system associated to an absorption refrigeration system, for the electricity and cold water production, and applied to two establishments, is presented. This system permits the recovery of waste heat, available between 600 deg C e 700 deg C. Initially, some technical information about the most diffusing types of the fuel cell demonstration in the world are presented. In the next step, an energetic, exergetic and economic analysis are carry out, seeking the use of fuel cells, in conditions of prices and interest of Brazil. In conclusion, the fuel cell cogeneration system may have an excellent opportunity to strengthen the decentralized energy production in the Brazilian energy scene. (author)
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Energy Technology Data Exchange (ETDEWEB)
Bombana, Clarice [Eletricidade Moderna (EM), Sao Paulo, SP (Brazil)
2001-10-15
The fuel cell is characterized as an important way of distributed energy generation, in this direction it can contribute for solution of demand control problems in relation to critical charging periods or energy rationing. Besides other benefits, can be highlighted the silent operation, utilization of residual heat and high quality of produced energy. Attentive to this tendency, COPEL and LACTEC have united efforts in order to diffuse this technology in Brazil.
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Energy Technology Data Exchange (ETDEWEB)
Restivo, T.A. Guisard; Mello-Castanho, S.R.H. [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia dos Materiais; Leite, D. Will [Instituto de Pesquisas e Estudos Industriais (IPEI/FEI), Sao Bernardo do Campo, SP (Brazil). Fac. de Engenharia Industrial
2009-07-01
A new method for direct preparation of materials for solid oxide fuel cell anode - Ni- YSZ cermets - based on mechanical alloying (MA) of the original powders is developed, allowing to admix homogeneously any component. Additive metals are selected from thermodynamic criteria, leading to compacts consolidation through sintering by activated surface (SAS). The combined process MA-SSA can reduce the sintering temperature by 300 deg C, yielding porous anodes. Densification mechanisms are discussed from quasi-isothermal sintering kinetics results. Doping with Ag, W, Cu, Mo, Nb, Ta, in descending order, promotes the densification of pellets through liquid phase sintering and evaporation of metals and oxides, which allow reducing the sintering temperature. Powders and pellets characterization by electronic microscopy and X-ray diffraction completes the result analyses. (author)
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Directory of Open Access Journals (Sweden)
Carlos Vergara-Uzcategui
2014-09-01
Full Text Available Los Linfomas Pulmonares Primarios son extremadamente raros (0,4% de los linfomas extraganglionares, y generalmente son de tejido linfoide asociado a mucosas (tipo MALT, con ocasionales linfomas de células grandes difusos. Los síntomas son inespecíficos, y casi la mitad de los pacientes son asintomáticos. Se presenta el caso de un paciente masculino de 56 años de edad, quien presentó durante 7 meses accesos diarios de tos seca, de predominio nocturno, asociados en el último mes a fiebre de 39ºC, disnea a medianos esfuerzos y expectoración verduzca. Los exámenes de laboratorio fueron normales. La radiografía de tórax mostró el mediastino ensanchado, un proceso en lóbulo medio con efecto atelectásico, y un nódulo en hemitórax izquierdo. La tomografía computarizada (TC torácica de alta resolución evidenció proceso alveolar derecho en lóbulo medio y un nódulo pulmonar izquierdo calcificado de tipo inespecífico. El estudio inmunohistoquímico de la biopsia pulmonar fue compatible con Linfoma de Células B de la zona marginal extraganglionar del tejido linfoide asociado a mucosa (Linfoma MALT de pulmón. La TC corporal y la Tomografía por Emisión de Positrones (PET evidenciaron importantes hallazgos complementarios para determinar la extensión de la enfermedad. El paciente se trato con quimioterapia y actualmente se encuentra en buenas condiciones, sin recidiva de la sintomatología. Dado lo infrecuente de la patología se presenta este caso y se hace una revisión de la literatura
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Directory of Open Access Journals (Sweden)
X. Clèries
2009-03-01
Full Text Available Las “Jornadas estatales de estudio y debate sobre el futuro de la formación integral del médico ¿bioingeniería o medicina?” que se realizaron en Barcelona el 8 y 9 de febrero de 2008 fueron el marco para que un grupo de trabajo abordara el tema de las fortalezas y debilidades de la formación actual del médico. Las principales aportaciones se estructuraron en los tres niveles educativos siguientes: pregrado, posgrado y formación continuada. Se destacó la necesidad de una formación integral y psicosocial en la enseñanza de pregrado, la conveniencia de una estructuración troncal de la formación de posgrado para conseguir una mayor transversalidad de la competencia del médico y la contextualización de la formación continuada en el desarrollo profesional de cada médico. El predominio de los conocimientos biomédicos y tecnológicos en la formación actual del médico contrastan con las demandas de carácter psicosocial de una gran parte de la población en el sistema sanitario.The “National Conference for study and debate on the future of the integral training of doctors: bioengineering or medicine?” that were realized in Barcelona on February 8-9th, 2008 it was the context so that a work group was carried out on the topic about strengths and weaknesses of the current training of physicians. The main contributions were structured around three educational levels: undergraduate, postgraduate and continuing education. In the undergraduate level was emphasized the need to achieve an integral and psychosocial education. The postgraduate education should have a core subject in order to acquire a better global understanding of doctors' competences. Continuing medical education in the context of professional development of every physician. The predominance of the biomedical and technological knowledge in the current training of doctors contrasts with psychosocial demands of the population of healthcare system.
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Redes de energía en la Argentina del siglo XXI. Proyectos locales innovadores
Directory of Open Access Journals (Sweden)
Silvina Carrizo
2015-04-01
Full Text Available En Argentina se construyeron de forma pionera, extensas redes de electricidad, gas y combustibles. El 98% de los hogares están conectados a la red eléctrica y el 51% de la población tiene acceso al gas natural por red (INDEC 2012. A pesar de la cobertura energética amplia, aún persisten en el país algunas regiones -como el Noroeste de la Provincia de Buenos Aires NOBAdonde las redes no llegan o tienen menor densidad. La región NOBA, situada entre las ciudades de Rosario y Buenos Aires, que cuentan con infraestructura considerable para su aprovisionamiento, presenta redes eléctricas y gasíferas poco densas -especialmente hacia el interior- y escaso desarrollo de fuentes de energías alternativas. En materia de gas, faltan gasoductos troncales o regionales. En el sistema eléctrico, hay poca capacidad de generación y se necesita mayor interconexión. Desde distintos niveles se han promovido alternativas en materia de producción, transporte y distribución de energía, pero los avances aún no alcanzan para asegurar la resiliencia energética enla región NOBA. En un contexto de esta índole, actores locales se han organizado para satisfacer sus necesidades energéticas con proyectos nuevos de transporte de gas y de aprovechamiento de recursos locales renovables, con un potencial que aún no ha sido puesto en valor. Abordando proyectos energéticos locales y regionales, este trabajo propone reflexionar acerca de la nueva geografía que podría delinearse en la producción y circulación de la energía, más flexible, fiable y sustentable, fomentando la innovación y la productividad, así como la equidad regional.
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Directory of Open Access Journals (Sweden)
B. Gal-Iglesias
Full Text Available Introducción. El estudio integrado de la fisiología y la anatomía constituye una asignatura troncal dentro de las titulaciones de ciencias de la salud. La adaptación de la enseñanza de esta materia al estándar de Bolonia supone un reto metodológico dada su complejidad curricular y sus perfiles competenciales específicos. Objetivos. Evaluar experimentalmente una metodología mixta en la enseñanza de la fisiología y anatomía tanto en los resultados del aprendizaje como en la adquisición de competencias de los alumnos, así como desarrollar un baremo de medición del aprendizaje. Sujetos y métodos. Se comparan los resultados del aprendizaje en la diplomatura de podología de la Universidad Europea de Madrid entre un grupo control (metodología clásica: lección magistral y uno experimental (metodología mixta: problemas, casos clínicos, trabajo en grupo y lección magistral. Resultados. Se muestra que con una aproximación mixta los alumnos adquieren habilidades y competencias a lo largo del curso, estabilizándose el aprendizaje lo suficiente y equilibrándose las diferencias individuales, en contraste con el grupo control. Esta homogeneización del aprendizaje se manifiesta como una menor variabilidad de la nota media de los exámenes en el grupo experimental, e indica el soporte que supone el método mixto para el aprendizaje de los alumnos con mayores dificultades. Se detecta una fuerte regresión lineal entre la asistencia a clase y los resultados del aprendizaje, y se confirma la importancia de la supervisión del proceso de aprendizaje por parte del profesor. Conclusión. El método mixto de enseñanza de la fisiología y la anatomía permite a los alumnos adquirir habilidades y competencias a lo largo del curso, equilibrando las diferencias como parte del proceso de aprendizaje.
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Energy Technology Data Exchange (ETDEWEB)
Macedo, Marfran C. de; Nascimento, Rubens M. do; Martinelli, Antonio E.; Melo, Dulce M.A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)
2004-07-01
The fuel cells if constitute currently as a promising alternative modular generation of electric energy to leave of chemical energy. The SOFCs is distinguished as promising for the industry of the oil, therefore they can use the produced natural gas in the platforms as combustible, allowing generation of raised power electric.The material of cathode constituent of the cell are oxides with perovskites structure, normally doped with a earthy-alkaline element (Sr{sup +3}). In this work, two compositions of the La{sub 1-x}Sr{sub x} MnO{sub 3} system were synthesized (x = 0,15 and 0,30), through the Pechini method and after resultants of the process they were characterized by X- Ray diffraction, Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TG/DTG) and laser grain size analysis. The systems in study shown similar behavior how much to the results of absorption in the region of infra-red ray and TG/DTG, therefore if it can prove the loss of organic substance with the increase of the temperature.The average particle diameter for the two systems also increased gradually with the temperature. In general way the synthesis method was satisfactory for the formation of the perovskites phase in the two studied compositions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Perona, Marina; Dagrosa, Maria A; Pisarev, Mario A; Juvenal, Guillelrmo J [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiogiologia; Pagotto, R; Pignataro, O [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina). Instituto de Biologia y Medicina Experimental; Casal, M [Instituto Nacional de Oncologia ' Angel H. Roffo' , Buenos Aires (Argentina)
2007-07-01
epidemiologicos han demostrado que la exposicion a altas dosis de radiacion externa incrementa la frecuencia de neoplasias de tiroides, particularmente cuando la misma ocurre en la niniez o en la adolescencia. El uso de radioprotectores de la tiroides seria de utilidad para evitar efectos tumorigenicos en la glandula cuando la radiacion ionizante en la zona del cuello es la unica terapia posible. Objetivos: Estudiar el posible efecto radioprotector de la droga antitiroidea 6 propil-2 tiouracilo (PTU). Se cultivaron celulas tiroideas normales (linea FRTL-5 de rata) y patologicas (lineas de cancer humano tiroideo anaplasico ARO). Las mismas fueron irradiadas con una fuente de 60Co (1Gy/min) en dosis variables entre 1 y 8 Gy, en presencia y ausencia de PTU (1 mM). A posteriori se evaluo el danio post radiacion mediante el ensayo de formacion de colonias tomando la fraccion de sobrevida (FS) como indicador del efecto. Resultados: La FS aumento respecto del Control en ambas lineas celulares para todas las dosis utilizadas. La relacion PTU vs. Control fue de 2,3 y 2,7 para las celulas ARO y FRTL-5 respectivamente. El efecto radioprotector del PTU es el mismo si es agregado 24 hs antes o inmediatamente post irradiacion. Dado que se ha demostrado que el aumento de la radioresistencia de los tejidos puede inducirse mediante la estimulacion de las vias del AMP ciclico (cAMP), se midieron los niveles del segundo mensajero luego de incubar las lineas celulares durante 5, 24, 48 y 72 horas con diferentes concentraciones de PTU (0; 0,1 mM; 1 mM y 2 mM). El PTU aumento los niveles intra y extracelulares del cAMP en todos los tratamientos. Se observo un pico a las 24 hs en los niveles extracelulares incubados con PTU 1 mM de 36,97 {+-} 6,37 (fmol/{mu}g de prot) vs Control 16,67 {+-} 3,92 (fmol/{mu}g de prot). El efecto radioprotector del PTU fue mimetizado por el cAMP. Conclusion: El PTU ejerce un efecto radioprotector estimulando la via del cAMP. (autor)
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Energy Technology Data Exchange (ETDEWEB)
Greiff, D. [Marquette University, School of Medicine, Milwaukee, WI (United States)
1962-02-15
de oxido de tritio por huevo y parcialmente en los grupos con 22,5 y 11,2 mcuries/huevo. El autor obtuvo resultados similares a los anteriores por inyeccion de oxido de tritio, a razon de 1 mcurie por cada 10{sup 8} celulas, en cultivos de una sola capa de celulas KB infectadas con R. mooseri o R. akari. Al inyectar oxido de tritio en huevos fecundados antes de inocularlos con virus de la gripe, se observa una disminucion del periodo de latencia correspondiente a la liberacion del virus de la membrana corioalantoica. El autor encontro que dos horas despues de inocular los huevos con el agente infeccioso, la cantidad de virus en el liquido corioalantoico habia aumentado mil veces. Cuando aparecen cantidades detectables de virus en el liquido corioalantoico de los huevos testigo, ocho horas despues de la infeccion, la DI{sub 50} de los huevos tratados con tritio era 10{sup -5,6}; 24 horas despues de la infeccion, ambas series daban una DI{sub 50} de 10{sup -7.5}. Tambien aumenta la cantidad de virus en las membranas de los huevos tratados con tritio. Para liberar este virus, el autor aislo y lavo las membranas, las seco por liofilizacion y rompio las celulas por rehidratacion con agua destilada. (author) [Russian] Rost Jiickettsia mooseri (myshinogo tifa) znachitel'no vozrastal v zarodyshevyh jajcah, soderzhashhih okis' tritija na urovne 180, 90 i 45 millikjuri/jajco, i neznachitel' no -v jajcah, soderzhashhih 22,5 millikjuri/jajco; infekcii pri 11,2 millikjuri/jajco ne otlichalis' ot pokazanij kontrol'nogo opyta. Rost Rickettsia akari (rik- ketsioza) byl celikom zaderzhan v jajcah, soderzhashhih okis' tritija na urovne 180, 90 i 45 millikjuri/jajco, i chastichno - v gruppah s soderzhaniem 22,5 i 11,2 mil- likjuri/jajco. Rezul'taty, podobnye nazvannym vyshe, byli polucheny posle inokuljacii- okisi tritija (1 millikjuri na 10{sup 8} kletok) v odnoslojnye kul'tury kletok KV, zarazhennyh R. mooseri ili R. akari. Uvelichenie latentnogo perioda dlja vysvobozhdenija virusa
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Energy Technology Data Exchange (ETDEWEB)
Urquiza B, Gustavo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Sierra E, Fernando [Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico); Kubiak S, Janusz; Campos A, Rafael [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2003-10-15
A numerical investigation has been conducted to study the turbulent flow and the heat transfer in a blade turbine coolant passage involving a 180 degrees turn. The study provides a comparison test for two turbulence models. The numerical solution was conducted employing two models for turbulence, the renormalization Group Theory (RNG) and the Reynolds Stress Model (RSM), using a refined grid to model with detail the recirculating flow. Computations are performed with a commercial finite volume code which solves three dimensional, incompressible, Navier-Stokes and Energy equations. At the passage turn, significant secondary flows are present, formed by a pair of symmetrical vortices. Results have been compared against published experimental data for Re = 53 000. Very good agreement is achieved for the prediction of the local static pressure distribution along the passage. A strong effect of rotation has been observed mainly in the flow field as described in detail in the paper. [Spanish] En este trabajo se presenta una investigacion numerica para estudiar el flujo turbulento y la transferencia de calor en un conducto de enfriamiento de un alabes de turbina de gas con giro de 180 grados. El estudio proporciona una comparacion de resultados para dos modelos de turbulencia. La solucion numerica emplea dos modelos de turbulencia: el modelo de esfuerzos de Reynolds (RSM) y el modelo de la teoria del grupo de renormalizacion (RNG), utilizando una malla refinada para modelar con detalle el flujo de recirculacion. Los calculos fueron realizados con un codigo comercial de volumenes finitos el cual resuelve las ecuaciones tridimensionales de Navier-Stoke y de energia para flujo incompresible. En la seccion de giro del conductor, aparecen flujos secundarios significativos, formados por un par de celulas simetricas. Los resultados han sido comparados contra datos experimentales de la literatura para Re = 53 000. se obtuvo un buen acuerdo para la prediccion de la distribucion de
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Directory of Open Access Journals (Sweden)
Alexandre Alencar
1981-12-01
Full Text Available São estudados três casos de germinomas cerebrais, sendo um tópico, da região pineal, e dois ectópicos, chamados germinomas supra-selares ou quiasmáticos. Estes últimos parecem ser mais agressivos que os seus congeneres tópicos, pois alem de se disseminarem pelas cisternas basais, costumam infiltrar as paredes do III ventrículo, fórnix, hipotálamo, nervos e quiasma ópticos. Caracteristicamente produzem um enorme aumento das proteínas liquóricas, desacompanhado de uma pleocitose proporcional. As proteínas liquóricas aumentadas sao globulinas cujas reações mostram-se fortemente positivas, possivelmente produzidas pelas celulas de aspecto linfocitario que constituem parte desta neoplasia. O aumento das proteinas liquoricas e tao acentuado que em presenca de uma crianca ou adolescente com sindrome de hipertensão intracraniana, hiperproteinoraquia sem pleocitose e sinais clínicos ou radiológicos sugestivos de localização na base do crânio a possibilidade de um germinoma quiasmático deve ser seriamente considerada, pois o quadro e muito sugestivo.Three cases of Cerebral Germinomas, one of them situated in the pineal region (topical and two ectopical of the so called suprasellar or chiasmal Germinomas are studied. These last ones may be more aggressive than the congeneral topical ones, since besides it's dissemination throughout the basal cisternas they usually infilstrate into de walls of the III Ventricle, Fornix, Hypothalamus, Chiasma and Optic nervs. A high level of proteins in the spinal fluid without proportional increase of the cells is characteristic. Globulins are the predominant fraction of the increased spinal fluid proteins, as indicated by the highly positive laboratory test. These globulins are possibly produced by the lymphocytes which are part of this neoplasm. The high level of protein in the spinal fluid without proportional increase of the cells, in the presence of intracranial syndrome in a child or
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Energy Technology Data Exchange (ETDEWEB)
Florio, D.Z. de [UNESP, Araraquara, SP (Brazil)], e-mail: dzflorio@ipen.br; Fonseca, F.C.; Franca, Y.V.; Muccillo, E.N.S.; Muccillo, R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Berton, M.A.C.; Garcia, C.M. [LACTEC - Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil)
2006-07-01
A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). Ceramic single cells were fabricated by low-cost methods, and emphasis was given to the use of ready available raw materials. The whole project consisted of the preparation of the component materials - anode, cathode, and electrolyte - and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3} + NiO) anode / (ZrO{sub 2}:Y{sub 2}O{sub 3}) electrolyte / (La{sub 0.65}Sr{sub 0.35}MnO{sub 3} + ZrO{sub 2}:Y{sub 2}O{sub 3}) cathode have been prepared and tested at 700 deg C and 800 deg C after in situ H{sub 2} anode reduction. The main results show that the slurry coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)
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Directory of Open Access Journals (Sweden)
Arnaldo Tabares Olives
1982-06-01
Full Text Available Son presentadas las características citomorfológicas anormales encontradas en el LCR de dos pacientes, uno de ellos sufriendo de leucemia aguda a células plasmáticas y otro de linfoma mixto no Hodgkin. Se enfatiza la importancia del estudio del LCR en estas patologias.
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Directory of Open Access Journals (Sweden)
Manolete S. Moscoso*
2009-10-01
Full Text Available Resumen:El presente artículo revisa el concepto del modelo psicobiosocial presentado por Engel y los primeros estudios sobre lanueva ciencia de la psiconeuroinmunoendocrinología, publicados por Solomon en la década del 60', y Ader en la década del70'. Se hace mención a los avances modernos en tecnología médica y de laboratorio como el punto de partida de un extensonúmero de estudios multidisclinarios durante la década del 80' que demuestran la relación entre el cerebro, y los sistemasnervioso, endocrino e inmune en el desarrollo de enfermedades. Se hace un análisis del concepto actual del estrés y unabreve revisión de las respuestas emocional y fisiológica descritas por Lazarus, Cannon, Selye, respectivamente. Una nuevavisión acerca del estrés es presentada y se hacen las distinciones correspondientes en relación a la respuesta comportamentaldel estrés, estilo de vida, y el estrés crónico. Finalmente se discute brevemente acerca del impacto negativo del estréscrónico sobre la salud del individuo.Abstarct:This article reviews the biopsicosocial model provided by Engel and the first studies in the field ofpsychoneuroimmunoendocrinology published by Solomon during the 60's and Ader during the 70's. it is pointed out thatadvances in medical technology and laboratory facilitated the beginning of studies in this field during the 80's. Extensivedata reports conclusive evidence of the interconnections between the brain, the nervous, endocrine and immune systems andthe development of disease. We discussed the emotional and physiological responses to stress as described by Lazarus,Cannon, and Selye. A new vision about stress is presented, taking into account the behavioral response to stress, life style,and chronic stress. Finally, we discussed briefly about the negative impact of chronic stress on health.
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Manolete S. Moscoso*
2009-01-01
Resumen:El presente artículo revisa el concepto del modelo psicobiosocial presentado por Engel y los primeros estudios sobre lanueva ciencia de la psiconeuroinmunoendocrinología, publicados por Solomon en la década del 60', y Ader en la década del70'. Se hace mención a los avances modernos en tecnología médica y de laboratorio como el punto de partida de un extensonúmero de estudios multidisclinarios durante la década del 80' que demuestran la relación entre el cerebro, y los sistemasnervioso...
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Energy Technology Data Exchange (ETDEWEB)
Santoro, Thais Aranha de Barros
2004-07-01
Experimental studies to achieve an optimized behavior of a unit PEM-fuel cell with an active area of 25cm{sup 2} were carried out. Polarization curves, surface response methodology and regression methodology were used for the analysis. The different methodologies identified the interactions between the parameters that were studied. These parameters were, humidifying temperature, fuel cell operating temperature and the flows of hydrogen and oxygen. MEAs were produced by the spray and hot pressing hybrid method, developed at IPEN. The studies were done with these MEAs and equivalent commercial ones. The MEAs producing method used induced an important variation on the quantity of platinum in the electrodes. This fact has showed to have a great influence in the results. The optimized values were: oxygen flow from 30 to 35% of consume (70 to 65% of excess), fuel cell operating temperature from 60 to 62 deg C and 0.41 mg of platinum in the electrodes. The hydrogen flows and the humidifying temperature have not showed a major influence in the fuel cell behavior, in the studied variable range. (author)
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Directory of Open Access Journals (Sweden)
Arias Zabala Mario
2002-06-01
Full Text Available Se desarrolla un protocolo para la obtención y establecimiento de suspensiones celulares de E. cinerea. La concentración de las hormonas 2,4 D Y BAP tienen un efecto significativo en la formación de callos friables de E. cinerea, obteniendo una respuesta periódica en la formación de callos friables con respecto a la concentración de las hormonas. Puede obtenerse hasta un 90% de formación de callos friables con varias combinaciones hormonales; primero, con concentraciones alrededor de 3,0 mg/L de 2,4 D Y 1,0 mg/L de BAp, y segundo, alrededor de 6,0 mg/L de 2,4 D Y1,0 mg/L de BAP. A partir de los callos anteriores, se obtienen suspensiones celulares con un activo crecimiento celular, con tiempos de duplicación entre cuatro y siete días, y alcanzando densidades celulares de 15 g células secas/L. Las suspensiones de E. cinerea ofrecen una herramienta importante para la propagación de esta especie vía embriogénesis somática, estudio de biorreactores, producción de metabolitos secundarios y procesos de biotransformación.A protocol is developed for obtaining and establishment of E. cinerea cell suspension. The concentration of hormones 2,4 D and BAP have a significant effect in the formation of friable callus of E. cinerea, obtaining a periodic answer in the formation of friable callus with regard to hormones concentration. It can be obtained until 90% of formation of friable callus in several hormone combinations, first with concentrations around 3,0 mg/L of 2,4 D and 1,0 mg/L of BAP; and second, around 6,0 mgIL of 2,4 D and 1,0 mg/L of BAP. Using the last callus, cell suspensions are obtained with an active cellular growth, with times of duplication between 4 and 7 days and obtaining cell densities of 15 g of dry cells/L. The suspensions of E. cinerea offer an important tool for the propagation of this specie by somatic embryogenesis, bioreactors study, production of secondary metabolites and biotransformation processes.
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Energy Technology Data Exchange (ETDEWEB)
Chenlo, F.
2002-07-01
Two procedures (simplified and complete) to determine the operating cell temperature in photovoltaic modules operating in real conditions assuming isothermal stationary modules are presented in this work. Some examples are included that show the dependence of this temperature on several environment (sky, ground and ambient temperatures, solar irradiance, wind speed, etc.) and structural (module geometry and size, encapsulating materials, antirreflexive optical coatings, etc) factors and also on electrical module performance. In a further step temperature profiles for non-isothermal modules are analysed besides transitory effects due to variable irradiance and wind gusts. (Author)
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Barba Recreo, Paula
2018-01-01
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Cirugía. Fecha de lectura: 8-09-2017 La osteonecrosis de los maxilares relacionada con la toma de bisfosfonatos (BRONJ) es una patología de frecuencia creciente, asociada a estos fármacos antirresortivos de amplio uso. El principal reto en el manejo de BRONJ es la ausencia de un tratamiento efectivo establecido. El objetivo de este trabajo fue comparar diferentes tratamiento...
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Técnicas de diseño de pasarelas de Voip empleando estándares abiertos y código libre
Directory of Open Access Journals (Sweden)
Alian Manuel Capote Álvarez
2010-09-01
Full Text Available Normal 0 21 false false false ES-TRAD X-NONE X-NONE MicrosoftInternetExplorer4 st1:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} La transmisión de voz sobre redes de datos, es sin duda alguna el futuro de toda comunicación a nivel global, la cual se apoya en una serie de protocolos para la señalización y control de la llamada. El desarrollo de medios capaces de manejar comunicaciones de voz, video y datos de manera eficiente, ocasionará en el futuro cambio en precios, operación y estructura de negocios, modificando la naturaleza de la economía en el mercado de las telecomunicaciones. Estos sistemas deben contar con una infraestructura de conmutación y de transporte de datos para lograr un servicio flexible de control de elementos. La plataforma telefónica código abierto Asterisk, está diseñada para interactuar de forma consistente con el software y hardware telefónico existente, logrando la interconexión entre los diferentes protocolos de señalización, de una forma transparente para el usuario final. En este trabajo se proponen algunos procedimientos de diseño e implementación de pasarelas con líneas troncales de acceso a la Red Telefónica Pública Conmutada (PSTN, y su configuración para interoperar entre los distintos estándares de señalización de
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Energy Technology Data Exchange (ETDEWEB)
Perez, J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica], e-mail: joelma@iq.unesp.br; Pereira, J.T.; Saeki, M.J. [UNESP, Bauru, SP (Brazil). Faculdade de Ciencias
2006-07-01
Solid Oxide Fuel Cells (SOFC) are energy conversion systems of great interest for industrial applications because they present a high efficiency for energy generation and several advantages for the environment. In this work, perovskite type oxides La{sub 085}Sr{sub 0,15}MnO{sub 3}, La{sub 0,7} Sr{sub 0,3}MnO{sub 3}, La{sub 0,6}Sr{sub 0,4}MnO{sub 3}, La{sub 0,85}Sr{sub 0,15}CoO{sub 3}, La{sub 0,7}Sr{sub 0,3}CoO{sub 3}, La{sub 0,6}Sr{sub 0,4}CoO{sub 3}, La{sub 0.6}Sr{sub 0,4}Fe{sub 0,8}Co{sub 0,2}O{sub 3} e La{sub 0.6}Sr{sub 0,4}Fe{sub 0,4}Co{sub 0,6}O{sub 3} were prepared by a polymeric method with the purpose of using them as cathodes in SOFCs. The electrochemical cell was mounted utilizing YSZ (ZrO{sub 2} - 8 mol%Y{sub 2}O{sub 3}) disks as electrolyte, where a paste containing Pt was calcined onto one face while the other one was covered with the oxide materials synthesized ('screen printing'). The oxide materials prepared were characterized by X-ray diffraction, transmission electronic microscopy and thermogravimetry. The oxygen reduction reaction was studied by taking polarization curves in oxygen and/or air (800 deg C a 950 deg C). The best performance was obtained for 15 {mu}m thickness electrodes La{sub 0.6}Sr{sub 0,4}MnO{sub 3} and La{sub 0.6}Sr{sub 0,4}MnO{sub 3} with addition of dispersed Pt. (author)
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Energy Technology Data Exchange (ETDEWEB)
Moraes, L.P.R. de; Silva, E.L. da; Amico, S.C.; Malfatti, C.F., E-mail: eticiaprm@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)
2014-07-01
In this work, PtNi binary catalyst and pure platin catalyst were synthesized by the impregnation-reduction method, using Vulcan XC72R as support, for direct ethanol fuel cells. The composition and structure of the catalysts were analyzed by X-ray diffraction, the electrochemical behavior was evaluated by cyclic voltammetry and morphology of the catalysts was studied by high-resolution transmission electron microscopy. The results showed that the addition of Ni to Pt led to the contraction of the crystal lattice, increased the catalytic activity compared to pure Pt and initiated the electrooxidation of ethanol at lower potential. (author)
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Energy Technology Data Exchange (ETDEWEB)
Leite, Marco Antonio Haikal [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)
2004-07-01
Brazil has a large potential to install distributed generation systems, using natural gas or renewable like solar, wind or biomass energy. Regarding urban centers, natural gas fired cogeneration and other distributed energy technologies find economical applications. Cogeneration is defined as the generation of two kinds of useful energy from a single energy source. Usually, electrical energy and thermal energy as steam or hot water are produced. By using the absorption refrigeration cycle, chilled water can also be produced to be used in air conditioned systems, often called tri generation, a good alternative to industries, commercial buildings, shopping centers, hospitals, schools and universities. Micro turbines find utilization whenever natural gas is available, but not electricity, like gas compression installations, unmanned platforms or remote production fields. Fuel cells are used in systems requiring high levels of reliability or wherever the non availability cost is high. This paper describe technical and economical data related to PETROBRAS Research Center (CENPES) 3,200 kW electric energy and 1,000 RT chilled water cogeneration system, 200 kW fuel cell and 30 kW and 60 kW microturbines. (author)
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Directory of Open Access Journals (Sweden)
Fernando Ubatuba
1948-12-01
Full Text Available Surgical removal of large amounts of hepatic tissue in male albino rats results in a rapid and conspicuous raise in cellular nuclear volumes. Measurements were made exclusively in resting nuclei. This volume variation is transitory. Nuclear volumes return to the normal value withins 6 days of restoration. The higher value are abserved 48 hours after the hepatic removal, indicating probably that this effect is due to hydration of the nucei, as occurs in the cytoplasm. This hydration could be correlated to the mitotic activity of the renmant tissue since a peak of mitoses parallels the changes in the nuclear volumes.
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Energy Technology Data Exchange (ETDEWEB)
Bernardi Junior, Paulo
2004-07-01
In function of the necessity of electric energy as input of vital importance for the development of the country, this work aims at to offer plus an energy alternative for Brazil. The exploitation of the natural gas reserves recently discovered can be made through modern methods that give as priority the distributed generation and the low ambient impact. All these aspects can be gotten with the use of fuel cell, working with the remodelled natural gas. Increased to the factor of a low ambient impact in the proper generation, the project suggests that the generating source can be located next the consumer, diminishing still more the problems generated for transmission lines, fuel transport, etc. The fuel cell has received a great attention in the international community and some models, some already in commercial period of training, they have shown excellent possibilities of capsize to be one of the future technologies in the generation of electric energy with low ambient impact. (author)
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Energy Technology Data Exchange (ETDEWEB)
Queiroz, Rodrigo Guimaraes
2012-07-01
Despite the constant advances in the treatment of cancer, this disease remains one of the main causes of mortality worldwide. So, the development of new treatment modalities is imperative. Snake venom causes a variety of biological effects because they constitute a complex mixture of substances as disintegrins, proteases (serine and metalo), phospholipases A2, L-amino acid oxidases and others. The goal of the present work is to evaluate a anti-tumor activity of some snake venoms fractions. There are several studies of components derived from snake venoms with this kind of activity. After fractionation of snake venoms of the families Viperidae and Elapidae, the fractions were assayed towards murine melanoma cell line B16-F10 and fibroblasts L929. The results showed that the fractions of venom of the snake Notechis ater niger had higher specificity and potential antitumor activity on B16-F10 cell line than the other studied venoms. Since the components of this venom are not explored yet coupled with the potential activity showed in this work, we decided to choose this venom to develop further studies. The cytotoxic fractions were evaluated to identify and characterize the components that showed antitumoral activity. Western blot assays and zymography suggests that these proteins do not belong to the class of metallo and serine proteinases. (author)
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Orozco Alarcón, María Soledad
2012-01-01
El cultivo y la extracción del azúcar se desarrollaron en la época de Napoleón. La ruta de la caña fue de Oriente a Occidente, desde el Índico al Mediterráneo, llegando finalmente al Atlántico, fueron precisamente los indios los primeros en probar su sabor. Las primeras referencias históricas del azúcar fue en el año 4.500 a.C, hacia el año 510 a.C., el azúcar llega hasta Persia donde los soldados del Rey Darío fascinados por sus propiedades la denominaron "esa caña que da m...
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Renata Dezengrini
2010-10-01
Full Text Available A atividade de três fármacos antivirais (Aciclovir [ACV], Ganciclovir [GCV] e Foscarnet [PFA] foi testada in vitro frente aos herpesvírus bovino tipos 1 (BoHV-1, 2 (BoHV-2 e 5 (BoHV-5. Para isso, utilizou-se o teste de reducao de placas virais em cultivo celular, testando-se diferentes concentracoes dos farmacos frente a 100 doses infectantes para 50% dos cultivos celulares (DICC50 dos respectivos virus. Pelo teste de MTT (3-(4,5-Dimethylthiazol- 2-yl-2,5-diphenyltetrazolium bromide, verificou-se que concentracoes inferiores a 200ƒÊg/mL dos tres antivirais resultaram em indices de viabilidade de celulas MDBK e Hep2 superiores a 80%. Com base na concentracao citotoxica para 50% das celulas (CC50 e na concentracao dos farmacos efetiva para inibir em 50% o numero de placas virais (EC50, calculou-se o indice de seletividade (IS dos antivirais para os tres herpesvirus. Assim, o ACV demonstrou ser moderadamente ativo frente ao BoHV-1 (EC50: 112,9ƒÊg/mL e IS: 4,5, ao BoHV-2 (EC50: 114,2 ƒÊg/mL e IS: 4,5 e BoHV-5 (EC50: 96,9ƒÊg/mL e IS: 5,3. O GCV apresentou atividade moderada frente ao BoHV-2 (EC50: 33,5ƒÊg/mL e IS: 16,6 e, em menor grau, contra o BoHV-5 (EC50: 123,2ƒÊg/mL e IS: 4,5, sendo ineficaz frente ao BoHV-1 (EC50: 335,8ƒÊg/mL e IS: 1,7. O PFA apresentou atividade antiviral mais pronunciada, sendo o unico farmaco que, na concentracao de 100ƒÊg/mL, inibiu completamente a producao de placas pelos tres virus testados. O PFA foi o mais efetivo in vitro frente ao BoHV-1 (EC50: 29,5ƒÊg/mL e IS: 42,2, ao BoHV-2 (EC50: 45,2ƒÊg/mL e IS: 27,6 e ao BoHV-5 (EC50: 7,8ƒÊg/mL e IS: 160,6. Portanto, os resultados obtidos indicam que o PFA pode se constituir em um candidato para terapia experimental de infeccoes pelos herpesvirus de bovinos in vivo.The activity of three anti-herpetic drugs (Acyclovir [ACV], Gancyclovir [GCV] and Foscarnet [PFA] was tested against bovine herpesvirus 1 (BoHV-1, 2 (BoHV-2 and 5 (BoHV-5 in vitro using the
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Energy Technology Data Exchange (ETDEWEB)
Santos, Geyza Spigoti
2011-07-01
In the last decades, it has been given a great interest to investigations concerning natural, effective, nontoxic compounds with radioprotective potential together with the increasing utilization of different types of ionizing radiation for various applications. Among them propolis, a resinous compound produced by honeybees (Apis mellifera), has been considered quite promising, since it presents several advantageous biological characteristics, i. e., anti-inflammatory, antimicrobial, anticarcinogenic, antioxidant and also free radical scavenging action. The purpose of the present study was to evaluate the effect of Brazilian propolis, collected in the State of Rio Grande do Sul, on Chinese hamster ovary (CHO-K1) and human prostate cancer (PC3) cells, irradiated with {sup 60}Co {gamma} radiation. For this purpose, three interlinked parameters were analyzed: micronucleus induction, cell viability and clonogenic death. The choice of these parameters was justified by their biological significance, in addition to the fact that they are readily observable and measurable in irradiated cells. The cytogenetic data obtained showed a radioprotective effect of propolis (5-100 {mu}g/ml) in the induction of DNA damage for both cell lines, irradiated with doses of 1 - 4 Gy. The cytotoxicity assay, however, showed a prominent antiproliferative effect of propolis (50 - 400{mu}/ml) in PC3 cells irradiated with 5 G{gamma}. The survival curves obtained were adequately fitted by a linear-quadratic model, where the {alpha} coefficient was higher in CHO-K1 cells. Concerning the clonogenic capacity, PC3 cells were more radiosensitive than CHO-K1 cells at the higher doses of the survival curve. Propolis at the concentrations of 30 - 100 {mu}g/ml, did not influence the clonogenic potential of PC3 cells, since the survival curves, associated or not with propolis, were found similar, although the combined treatment in CHO-K1 cells exhibited a stimulating proliferative effect. The data obtained in vitro showed a potential use of propolis AF-08, a natural and nontoxic compound, in the prevention against the adverse effect of ionizing radiation, at the doses and concentrations here analyzed. (author)
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Energy Technology Data Exchange (ETDEWEB)
Fukurozaki, S.H.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de Processamento de Residuos
2006-07-01
Currently, platinum is the most feasible catalyst for the Proton Exchange Membrane Fuel Cells - PEMFC. Along with platinum's significant importance in this energy system are the high cost of this noble metal and its detrimental effects on the environment. Therefore, recycling this material seems as an alternative to decrease its impacts on the environment and, at the same time, to provide a reduction of the system's costs. A search was conducted for literature and studies about platinum recycling methods. However, only two techniques of platinum recovery, which are still in development, were found. In face of this situation, a recovery method of platinum from deactivated Membrane Electrode Assembly - MEA's was developed, with attention to aspects related to the environment and the necessary requirements for its primary recycling. The results found showed a high recovery ratio and a possibility to reintroduce this metal into the production cycle. (author)
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Energy Technology Data Exchange (ETDEWEB)
Pinto, Luiz Gustavo Teixeira [Hospital e Maternidade Marieta Konder Bornhausen, Itajai, SC (Brazil). Servico de Medicina Interna; Isberner, Rony Klaus [Hospital e Maternidade Marieta Konder Bornhausen, Itajai, SC (Brazil). Servico de Radiologia]. E-mail: ronyklaus@terra.com.br; Scolaro, Bruno Lorenzo [Universidade do Vale do Itajai, SC (Brazil). Curso de Medicina]. E-mail: brunoscolaro@yahoo.com.br; Sezerino, Daniel Oseias [Universidade do Vale do Itajai, SC (Brazil). Curso de Medicina. Disciplina de Anatomia Patologica; Almeida, Daniel da Silva [Hospital e Maternidade Marieta Konder Bornhausen, Itajai, SC (Brazil). Servico de Radiologia e Diagnostico por Imagem
2006-10-15
Desmoplastic small round cell tumor is a rare and highly aggressive neoplasm that predominantly occurs in young adult males. Pain and abdominal distention are frequent, ascites could be observed. His histogenesis is uncertain and the most common location is the peritoneal cavity. This tumor is characterized by presenting a distinct morphology and polyphenotypic differentiation. We present in this report the case of an adolescent admitted in the service of Internal Medicine and Radiology of the Hospital and Maternity Marieta Konder Bornhausen, Itajai, SC, Brazil, in year 2005. (author)
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Energy Technology Data Exchange (ETDEWEB)
Lorenzo, E.; Martinez, F.; Moreton, R.
2009-07-01
In some cases due to plants performance is not as correct as hoped, and in some other, simply because the nice colors of the thermographs resulted very attractive to plenty of people; many photovoltaic generators have been profusely thermography within the current year. It has caused a special interest on hot cells phenomenon, that is to say those cells which operate at a significantly higher temperature than other placed in the same panel. (Author) 4 refs.
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Energy Technology Data Exchange (ETDEWEB)
Mozer, Thiago Simonato; Passos, Fabio Barboza [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Quimica e de Petroleo. Lab. de Reatores, Cinetica e Catalise (RECAT)]. E-mail: mozer@vm.uff.br
2008-07-01
The selective CO oxidation in the presence of H2 was investigated on Au catalysts promoted with different amounts of Cu. Au catalysts were prepared by the deposition-precipitation method and exhibited a satisfactory activity at 50 deg C with adequate selectivity. The addition of Cu to Au/Al{sub 2}O{sub 3} catalysts caused an increase in the selectivity to CO oxidation due to an interaction between Au and Cu on the surface of the catalysts. However, this beneficial effect was limited to an optimal content of Cu. Through the temperature programmed reduction (TPR) and ultraviolet visible diffuse reflectance spectroscopy (UV-vis DRS) techniques, the formation of small bimetallic Au-Cu particles was verified. The best result was obtained with 2.5% Au-0.5% Cu/Al{sub 2}O{sub 3} catalyst, the CO conversion was higher than 95% and the selectivity was around 70% at 50 deg C. The catalysts showed stable catalytic activity during 24 hours time -on-stream. In the presence of H{sub 2}O and CO{sub 2}, a small decrease in the CO conversion was observed in the stability test, probably due to the deactivation caused by the CO{sub 2} presence. (author)
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Barcones Campo, Beatriz; Álvarez García, Jacobo; Calvo-Barrio, L.; Pérez Rodríguez, Alejandro; Romano Rodríguez, Alberto; Morante i Lleonart, Joan Ramon; Scheer, R.; Klenk, R.; Pietzker, Ch.
2004-01-01
En este trabajo se presenta un estudio detallado de los procesos implicados en la sulfurización de capas metálicas de Cu-In para la fabricación de células solares de CuInS2. Con este objeto, se ha desarrollado un experimento de sulfurización parcial de las capas, que han sido sometidas posteriormente a un tratamiento de selenización. El estudio de estas estructuras mediante Espectroscopía Raman y Espectroscopía de Electrones Auger (AES) ha permitido conocer algunos de los detalles de la reacc...
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Directory of Open Access Journals (Sweden)
Alejandro Soto Gutiérrez
2006-01-01
Full Text Available Las células embrionicas han sido estudiadas recientemente como un recurso atractivo para la construcción de órganos artificiales. La proliferación y subsiguiente diferenciación de las células embrionicas dentro de los mismos dispositivos artificiales deben ser consideras. Recientemente, hemos desarrollado un hígado bioartificial usando una tela sintética con fibras huecas recubiertas con un poliaminouretano, el cual facilita la atracción celular dentro del dispositivo hepático. En esta ocasión hemos evaluado la capacidad de atracción celular de las células embrionicas y de cuerpos embrionicos así como la funcionalidad de hepatocitos derivados de células embrionicas de raton en la fibra sintetica. Para diferenciar un gran numero de hepatocitos derivados de las celulas embrionicas, nosotros formamos cuerpos embrionicos y los expusimos al factor 2 de creciemiento de los fibrobastos y a la forma sintetica del factor de crecimiento de los hepatocitos asi como dimetilsulfoxido y dexametasona. La adherencia celular y morfología sobre la fibra sintetica fue evaluada regularmente usando microscopio electronico (SEM. Para evaluar la diferenciación celular examinamos la expresión del gen de la albúmina. Para probar la función de los hepatocitos derivados in Vitro, nosotros evaluamos la capacidad de metabolizar amonio y lidocaina, encontramos que las células cultivadas sobre la fibra sintética expresan y secretan mayores cantidades de albúmina y metabolizan significativamente mejor que los controles. En este trabajo de investigación hemos demostrado que existe una adecuada atracción de las células embrionicas de ratón cultivadas sobre la fibra sintética y que también son capaces de diferenciarse en hepatocitos funcionales. Por esta razón, el cultivo y subsiguiente diferenciación de las células embrionicas sobre la fibra sintética podría ser útil en el desarrollo de biosoportes para la construcción de hígados bio
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Directory of Open Access Journals (Sweden)
Suzan Kelly Vilela Bertolucci
2010-07-01
Full Text Available Os oleos essenciais sao principios odoriferos armazenados em celulas especiais da planta. O oleo essencial no genero Hyptis e usado como anestesico, antiespasmodico, antiinflamatorio e pode induzir aborto em doses elevadas. O objetivo deste trabalho foi avaliar a influencia da sazonalidade no teor e composicao do oleo essencial de Hyptis marrubioides. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos (inverno, primavera, verao e outono e seis repeticoes, totalizando 60 plantas. O oleo essencial foi extraido por hidrodestilacao, em aparelho de Clevenger. A analise qualitativa do oleo essencial foi por cromatografia em fase gasosa (CG/EM. Na estacao do verao, as folhas das plantas de H. marrubiodes apresentaram os maiores teores de oleo essencial. Nas demais estacoes, os teores de oleo essencial obtidos foram semelhantes entre si. Os componentes majoritarios no oleo essencial foram os monoterpenoides α-tujona e β-tujona. As concentracoes relativas dos picos correspondentes a β-tujona nao apresentaram diferencas consideraveis nas quatro estacoes. Os sesquiterpenoides oxigenados (cedrol e cariofilenol e nao-oxigenados (α-copaeno, β-cariofileno, germacreno D e cadaleno foram encontrados em menores quantidades no oleo essencial, entretanto observam-se diferencas quantitativas ao longo das estacoes.Essential oils are odorous principles stored in special plant cells. The essential oil in the Hyptis genus is traditionally used as an anesthetic, antispasmodic, antiinflammatory, and can induce abortion in high doses. The purpose of this work was to evaluate the influence of seasons in essential oil content and chemical composition of species H. marrubioides. A completely randomized complete design was used with four treatments (winter, spring, summer and autumn and six replications, totaling 60 plants. The essential oil was obtained by hydrodistillation with a Clevenger apparatus. The qualitative analysis of the
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Directory of Open Access Journals (Sweden)
Yoshinobu Nagasse
2010-12-01
Full Text Available OBJETIVO: os autores realizaram um estudo e compararam o resultado radiográfico no uso de hidroxiapatita e enxerto de crista ilíaca (autólogo no tratamento cirúrgico de hérnia discal cervical em um nível, sendo realizada artrodese cervical anterior com placa. MÉTODOS: foi realizado estudo retrospectivo com pacientes submetidos à artrodese cervical comparando-se dois grupos de dez pacientes: um em que foi utilizado enxerto de hidroxiapatita e outro em que foi utilizado enxerto de crista ilíaca (autólogo. Radiografias pós-operatórias foram mensuradas e comparadas, à busca de perdas de alinhamento angular. RESULTADOS: os dois tipos de enxerto demonstraram manter alinhamento em taxas similares, sendo observada consolidação óssea em todos os pacientes. O estudo não mostrou fragmentação do enxerto de hidroxiapatita ou soltura do material de síntese. CONCLUSÃO: nesta pequena série de casos não foi observada diferença significativa entre os resultados da artrodese cervical anterior com enxerto de hidroxiapatita em relação ao enxerto autólogo de ilíaco.OBJETIVOS: los autores realizaram un estudio y compararon el resultado radiográfico en el uso del hidroxiapatita y injerto de cresta ilíaca (autólogo, en el tratamiento quirúrgico de hernia discal cervical en un nivel, siendo realizada artrodesis cervical anterior con placa. MÉTODOS: fue realizado un estudio retrospectivo con pacientes, que habían sido sometidos a la artrodesis cervical con injerto de hidroxiapatita o injerto de cresta iliaca b.z autologa. Las radiografías postoperatorias habían sido mensuradas y comparadas, buscando para las pérdidas de alineación angular. RESULTADOS: los dos tipos de injerto habían demostrado manutención de alineación similares, donde la consolidación fue observada en todos los pacientes. El estudio no demostró la fragmentación del injerto de hidroxiapatita o de soltar el material de síntesis. CONCLUSIÓN: en esta peque
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Recursos territoriales y procesos geográficos: el ejemplo de los recursos turísticos
Directory of Open Access Journals (Sweden)
Barrado Timón, Diego A.
2011-06-01
Full Text Available The concept of resource, with a long geographical tradition, and essential to understand society-space relations, has lost presence when explaining the processes of functionalization, occupancy and transformation of the territory. The idea here is to remark the explicative potential of the concept but also its complexity and the need of including it in a wider framework that considers cultural, social, economical and technical processes, as well as the agents involved and their interests and capabilities. Bringing the existence up of a main geographical subject in the degree of Tourism called Territorial Tourist Resources, at the end of this text the conceptual approaching is specifically illustrated with geographical resources for tourism.
El concepto de recurso, de larga tradición geográfica y esencial para entender las relaciones sociedad-medio, ha ido perdiendo presencia a la hora de explicar los procesos de funcionalización, ocupación y transformación del territorio. Se trata aquí de resaltar su potencialidad explicativa pero también su complejidad, y la necesidad de incluirlo en un marco más amplio que atienda también a los procesos culturales, sociales, económicos y tecnológicos, así como a los agentes intervinientes, sus intereses y sus capacidades. Aprovechando la existencia de una asignatura troncal de Geografía en la Diplomatura en Turismo que lleva por título Recursos territoriales turísticos, al final del texto se ejemplifican los planteamientos conceptuales con el caso de los recursos geográficos para el turismo. [fr] Le concept de ressource, avec une longue tradition géographique et essentiel pour comprendre les relations société-milieu, a perdu importance au moment d’expliquer les processus de fonctionnalisation, occupation et transformation du territoire. Il s’agit ici de souligner sa potentialité explicative, mais aussi sa complexité et la nécessité de l’inclure dans un cadre plus vaste ce -
Directory of Open Access Journals (Sweden)
Jean-Luc M.J Antoine
2004-01-01
Full Text Available La idea de la ciudad utópica es casi tan antigua como el pensamiento humano. Ella consiste en una sociedad teóricamente perfecta y transparente donde todo está perfectamente controlado y, en consecuencia, los ciudadanos podrían alcanzar la felicidad. En este artículo pretendemos reflexionar, mediante una perspectiva holística -y con ejemplos prácticos como la clonación, células troncales y eugenismo-, acerca de la sociedad genética actualmente en ciernes, la que, a pesar de presentarse como una potente herramienta para alcanzar una ciudad utópica, sería hoy imposible por los numerosos riesgos y peligros existentes. Por tanto, creemos importante un análisis sobre la bioética y el progreso, antes de seguir adelanteA idéia da cidade utópica é quase tão antiga como o pensamento humano. Consiste numa sociedade teoricamente perfeita e transparente onde tudo está perfeitamente controlado, onde consequentemente os cidadãos poderiam alcançar a felicidade. Neste artigo pretendemos refletir, mediante uma perspectiva holística -e com exemplos práticos como a clonagem, células tronco e eugenismo-, acerca da sociedade genética atualmente em cernes, a que, apesar de apresentar-se como uma potente ferramenta para alcançar uma cidade utópica, hoje seria impossível pelos numerosos riscos e perigos existentes. Portanto, cremos que é importante e necessário fazer uma análise sobre a bioética e o progresso, antes de seguir enfrenteThe idea of an utopian city is almost as old as human thinking. It consists in a society theoretically perfect and transparent where everything is under control, so that citizens could achieve happiness. In this article, using a historical perspective, we pretend to reflect, with practical examples such as cloning, stem cells and eugenics, on a genetic society which is blossoming and in spite of presenting itself as a strong tool to achieve the utopian city, this would not be possible due to the warning for
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Energy Technology Data Exchange (ETDEWEB)
Geraldes, Adriana N.; Zen, Heloisa A.; Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: angeral@ipen.br
2007-07-01
Grafting of styrene onto polyvinylidenefluoride (PVDF), polytetrafluoroethylene (PTFE) was studied using styrene/toluene solutions. First, PTFE and PVDF films were prepared and the process was conducted by radiation induced graft polymerization of styrene, by a Co{sup 60} source. Films of PTFE and PVDF were immersed in styrene/toluene at 1:1 (v/v) concentration and then submitted to gamma radiation at 20 kGy doses. After irradiation, the samples were evaluated at the period of 21 days at room temperature in order to observe the grafting degree. Chemical changes in the PVDF and PTFE films after styrene grafting were monitored and the results were evaluated by FTIR, DSC, TGA and degree of grafting (DOG). The ion exchange capacity (IEC) after sulfonation of 1, 2 and 24 hours were also determined. (author)
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Energy Technology Data Exchange (ETDEWEB)
Ramos, C.Z.; Dantas, R.; Oliveira, I.S. de; Azevedo, C.M.N.; Pires, M. [Pontificia Univ. Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Quimica; Canalli, V. [Pontificia Univ. Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Engenharia
2006-07-01
In low temperature fuel cells the main part is the membrane electrode assembly (MEA). The gas diffusion layer is a component of the MEA, being a composite material constituted by carbon powder and polytetrafluoroethylene, used to increases hydrofobicity, fundamental characteristic in water transport into system. In this work methods were adapted with the aim to a better characterization of the diffusion layer by the measuring the following parameter: contact angle and hysteresis; morphology, thickness and porosity. From these characterization results optimized MEAS will be produced to better fuel cell performance. (author)
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Energy Technology Data Exchange (ETDEWEB)
Bueren, J. A.
2011-07-01
Since 1961, they year when the first trial that characterized the behaviour of a stem cell in mice exposed to high doses of radiation was described, research in this field has proceeded at an unpredictable place. Knowledge of the function of hematopoietic stem cells which are responsible for forming blood cells facilitated the development of therapies based on the transplant of bone marrow and other cell source, e. g. blood from the umbilical cord. These breakthroughs, together with the progress of molecular biology and virology, made it possible to manipulate the genome of hematopoietic stem cells so effectively and safely that the transplant of genetically modified cells has become a variable therapeutic alternative for the treatment of certain genetic diseases and also cancer. This brief article describes some of the contributions that our Hematopoiesis and Gene Therapy Division of the CIEMAT and the CIBER for Rare Diseases has been developing in this fascinating field of stem cells and gene therapy, in the context of the international research being carried out in this area. (Author) 34 refs.
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Energy Technology Data Exchange (ETDEWEB)
Cunha, S.C.S.; Corgozinho, K.B.; Ferreira, A.M.R, E-mail: simonecsc@gmail.com [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Carvalho, L.A.V. [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil); Holguin, P.G.
2014-02-15
The efficacy of radiation therapy for feline advanced cutaneous squamous cell carcinoma was evaluated. A full course radiation therapy protocol was applied to six cats showing single or multiple facial squamous cell carcinomas, in a total of seven histologically confirmed neoplastic lesions. Of the lesions, one was staged as T{sub 1}, and six as T{sub 4} according to WHO staging system of epidermal tumors. The animals were submitted to twelve radiation fractions of 4 Gy each, on a Monday-Wednesday-Friday schedule, and the equipment used was an orthovoltage unit. Energy used was 120 kV, 15 mA and 2 mm aluminum filter. The cats were evaluated during the treatment and 30 and 60 days after the end of the radiation therapy. In this study, 87% of the lesions had complete remission and 13% partial remission to the treatment. Side effects were considered mild according to Veterinary Radiation Therapy Oncology Group Toxicity criteria, and included erythema, epilation and rhinitis. Radiation Therapy was considered safe for feline cutaneous squamous cell carcinoma, leading to mild side effects and can represent a good therapeutic option. (author)
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Energy Technology Data Exchange (ETDEWEB)
Neto, P.P.B.; Grilo, J.P.F.; Souza, G.L.; Macedo, D.A.; Paskocimas, C.A.; Nascimento, R.M., E-mail: pbritoneto@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)
2012-07-01
Reducing the operating temperature of solid oxide fuel cells (SOFC) for the range between 500 and 700°C is one of the challenges which more has aroused the interest of research in SOFC in recent years. In this context, the bilayer anode/electrolyte composed of a porous support based on Ni-doped ceria (anode) and a ceria doped gadolinia (CGO) electrolyte, presents itself as one of the half-cell configurations of the most interest towards the production of electricity in the operating logic of a SOFC. In this work, CGO films were successfully prepared on NiO-CGO substrates using the resources of the screen-printing technique. The bi-layers were co-sintered between 1350 and 1450 ° C for 4 h and then characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS). The results showed good adhesion at the film/substrate interface and no cracks in the films. (author)
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Energy Technology Data Exchange (ETDEWEB)
Gastaldi, Andre Fava; Souza, Teofilo Miguel de; Mesquita, Rafael Pimenta [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Centro de Energias Renovaveis], e-mail: teofilo@feg.unesp.br
2004-07-01
With the growing electric energy use demand and almost not expansion of the energy mesh (basically composed by hydroelectric plants) existing in the country, several others methods of alternative energy generation may be necessary. Beyond that, the usually employed energy is becoming much more costly, rarer and politically more impracticable like burn fuels as oil and coal. The use of renewable approaches of energy, that are 'infinite' energies (as the wind and the light of the sun, for example), can become an excellent alternative. In this new energy group, the solar energy transformed by the use of photo voltage cells is becoming very important. The 'clear' solar radiation tends to be a more intelligent and practical option, and the future technology of energy storage will be able to solve the problem of the regions that have less sunny days. Its main advantages on the other alternative sources of energy are the trustworthiness and the previsibility. Its biggest disadvantage consists on the fact that technical limitations can not allow a solar energy generator to distribute electricity for a city. It is interesting to notice that with the development of projects as this in alternative energy, isolated areas that does not access electricity distribution network (as some far regions), it has become the most viable option of generation of electric energy. Another point is that even with the distribution network it has to be checked if it is possible to use this electricity consulting the company credential that work at those localities of consumption. Moreover, many regions of the country already installed the solar energy system for water heating, confirming that, the existing structure allows the installation of a a solar cells generation energy system without many problems. In this project, we introduce a method for electric energy generation by solar cells for rural population of low gains. This option uses low cost materials but with a good quality level. Also presents a comparative table showing a kit for rural areas employment which is constituted of: 3 fluorescent light bulbs (power of 9 W, 3 hours per day, 7 days per week), 1 T.V. of 14' ' (power of 15 W, 3 hours per day, 7 days per week) and 1 Radio (power of 5 W, 6 hours per day, 5 days per week). (author)
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Energy Technology Data Exchange (ETDEWEB)
Loureiro, Felipe A.M.; Rocco, Ana Maria [Grupo de Materiais Condutores e Energia, Escola de Quimica, Universidade Federal do Rio de Janeiro, RJ (Brazil)], e-mail: amrocco@eq.ufrj.br; Pereira, Robson Pacheco [Instituto de Ciencias Exatas, Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil)
2011-07-01
In the present work, proton conductive membranes based on IPN matrices doped with H{sub 3}PO{sub 4} were developed. The characterization by infrared vibrational spectroscopy evidenced the polymerization of DGEBA and the immobilization of PEI chains, originating a structure containing basic sites suitable for proton coordination and conduction. The FTIR characterization evidenced the polymerization of DGEBA in the presence of PEI thus forming Semi-IPN membranes which, after doped with H{sub 3}PO{sub 4}, exhibited conductivity values of 10{sup -4} W{sup -1}cm{sup -1} at room temperature and 10{sup -3} {omega}{sup -1}cm{sup -1} at 80 degree C, as well as a dependency of conductivity with temperature following the Arrhenius model. The activation energy values (14,33 and 12,96 kJ.mol{sup -1}) indicated a proton conduction mechanism predominantly vehicular in the matrices studied under 100% relative humidity. (author)
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Energy Technology Data Exchange (ETDEWEB)
Brioude, Michel de Meireles; Sodre, Livia Farias; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)
2006-07-01
In this work two series of membranes were prepared; they were based on hybrid organic-inorganic or composite materials and presented potentiality for application in Proton Exchange Membrane Fuel Cell, PEMFC. The polymeric phase was constituted of poly(dimethylsiloxane), PDMS, crosslinked with tetra ethoxysilane, TEOS, with a 70%/30% ratio. Phosphotungstic acid (PWA) or the sodium monododecylsulphate (MDS), as proton conductors, were added to the inorganic network, close to the gel point; the mixtures were transferred to a cast. The films were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The membranes showed good properties, as flexibility, thermal and mechanical stability with potentiality to be used as conducting membranes in technological applications. (author)
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Energy Technology Data Exchange (ETDEWEB)
Rodrigues, Leticia Jenisch
2011-01-15
In its classical formulation, the Dancoff factor for a perfectly absorbing fuel rod is defined as the relative reduction in the incurrent of resonance neutrons into the rod in the presence of neighboring rods, as compared to the incurrent into a single fuel rod immersed in an infinite moderator. Alternatively, this factor can be viewed as the probability that a neutron emerging from the surface of a fuel rod will enter another fuel rod without any collision in the moderator or cladding. For perfectly absorbing fuel these definitions are equivalent. In the last years, several works appeared in literature reporting improvements in the calculation of Dancoff factors, using both the classical and the collision probability definitions. In this work, we step further reporting Dancoff factors for perfectly absorbing (Black) and partially absorbing (Grey) fuel rods calculated by the collision probability method, in cluster cells with square outer boundaries. In order to validate the results, comparisons are made with the equivalent cylindricalized cell in hypothetical test cases. The calculation is performed considering specularly reflecting boundary conditions, for the square lattice, and diffusive reflecting boundary conditions, for the cylindrical geometry. The results show the expected asymptotic behavior of the solution with increasing cell sizes. In addition, Dancoff factors are computed for the Canadian cells CANDU-37 and CANFLEX by the Monte Carlo and Direct methods. Finally, the effective multiplication factors, k{sub eff}, for these cells (cluster cell with square outer boundaries and the equivalent cylindricalized cell) are also computed, and the differences reported for the cases using the perfect and partial absorption assumptions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Kluke, M.
2010-07-01
The solar industry is booming. thin-film technology is experiencing a high demand as promised cost advantages and currently is providing excellent results, while a range of efficiency reaches acceptable. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Furtado, Jose G.M.; Lopes, Francisco C.; Silva Junior, Fernando R.; Soares, Guilherme F.W.; Serra, Eduardo T. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)
2008-07-01
Power systems based on fuel cells have been considered for residential and commercial applications in energy Distributed Generation (DG) market as these systems can minimize their acquisition, installation and operation high costs. In this work we present an experimental analysis of a power generation system formed by a 5 kW proton exchange membrane fuel cell unit and a natural gas reformer (fuel processor) for hydrogen production, of the CEPEL's Fuel Cell Laboratory. It was determined the electrical performance of the cogeneration system in function of the design and operational power plant parameters. Additionally, it was verified the influence of the activation conditions of the fuel cell electrocatalytic system on the system performance. It also appeared that the use of hydrogen produced from the natural gas catalytic reforming provided the system operation in excellent electrothermal stability conditions resulting in increase of the energy conversion efficiency and of the economy of the cogeneration power plant. The maximum electrical efficiency achieved was around 38% and in all power range unit operated with average potential per single fuel cell higher than 0.60 V. (author)
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Energy Technology Data Exchange (ETDEWEB)
Azevedo, Dayse Caldas de; Souza, Adler de; Ferreira, Valdemar Stelita [NovoCell Sistemas de Energia S.A., Santa Barbara D' Oeste, SP (Brazil)
2008-07-01
Fuel cells present the potentiality to substitute the engines of internal combustion in vehicles and to supply energy for stationary use. This potentiality, however, not yet reflected in its introduction in the market with regular lines of production, because of its high cost and lack of criteria that demonstrate its reliability and durability. These subjects are the main goals of the programs of development of fuel cells worldwide. NovoCell is a Brazilian company whose objective is to develop and to produce hydrogen/air fuel cells for stationary generation. All the project is guided by the use of technologies/processes and materials that allow production in large scale and to a competitive cost, giving support to a continuous program of innovation and development of the product. In this work the technological solutions developed by the company are presented. (author)
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Directory of Open Access Journals (Sweden)
Franco E. Chiarini
2010-12-01
Full Text Available The mature fruits of 10 South American species of Solanum sect. Torva were studied. Cross and longitudinal microtome sections, stained with astra blue/basic fuchsin, were made for microscopic examination. All species present an epidermis formed by a unistrate layer of small, isodiametric cells, with dense content and cellulosic walls. Immediately below, a hypodermis is always found, consisting of a well-defined layer of lignified cells with a single calcium oxalate crystal occupying the whole lumen of each cell. This is followed by one layer of cellulosic, isodiametric cells with dense cytoplasm and then several collenchymatous layers, sometimes with sclerified cell walls. The mesocarp comprises two zones histologically differentiated: an external one (formed by regular, vacuolated, medium-sized cells with small intercellular spaces, and an internal one, commonly juicy, and developing proliferations among the seeds. The fruits analyzed are alike, and despite some particularities, they can be classified as berries in the conventional sense. All the traits examined agree with the ornithochorous dispersal syndrome. The homogeneity in fruit traits may be due to shared habit, habitat and sexual system.Se estudiaron los frutos maduros de 10 especies sudamericanas de Solanum sect. Torva. Se examinaron en microscopio cortes microtómicos transversales y longitudinales teñidos con azul astral/fucsina básica. Todas las especies presentaron una epidermis unistrata de células pequeñas, isodiamétricas, de contenido denso y paredes celulósicas. Inmediatamente por debajo se encontró siempre una hipodermis, formada por una capa bien definida de células lignificadas con un cristal de oxalato de calcio en el lúmen de cada célula. A continuación se halló otra capa de celulas isodiamétricas, celulósicas, de contenido denso, y luego varias capas de colénquima, en ocasiones con paredes esclerificadas. El mesocarpo presentó dos zonas histologicamente
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Energy Technology Data Exchange (ETDEWEB)
Berton, Marco Antonio Coelho; Garcia, Carlos Mario; Matos, Jeferson Hrenechen [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: felsky@latec.org.br, garcia@latec.org.br, jeferson.h@latec.org.br
2010-04-15
Solid electrolytes of BaCe{sub 08}Gd{sub O29} were prepared by the polymeric precursor method. X-ray diffraction data shows a single phase with orthorhombic crystalline structure. The densification process was followed by scanning electronic microscopy and apparent density measurements. The apparent density was developed for different temperatures of sintering, reaching > 96% for sintered temperature of 1550 {sup 0}C deg . The electrochemical impedance analysis was development in the temperature of 400-700 deg C, in air atmosphere at 700 deg C a value of 30,6 mS.cm{sup -1} was obtained. The results of conductivity have confirmed the gadolinium doped barium cerate has a great potential for use as solid electrolyte for intermediate temperature solid oxide fuel cell, at experimental controlled conditions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Almeida, Silvio Carlos Anibal de; Xavier, Bruno Domont; Gatti, George Cassani; Ribeiro, Rodrigo Minguita [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Mecanica]. E-mails: silvioa@gmail.com; brunodomont@gmail.com; gatti_ufrj@yahoo.com.br; rminguita@yahoo.com.br; Furtado, Jose Geraldo de Melo [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil). Dept. de Tecnologias Especiais]. E-mail: furtado@cepel.br
2006-07-01
This paper describes the essays performed with a polymeric membrane fuel cell (PEMFC) at the test laboratories of the ELETROBRAS Electric Energy Research Center (CEPEL/ELETROBRAS) manufactured by the Eletrocell, which allows to study the influence of some functional parameters (voltage, current, mass and pressure fluxes)
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Energy Technology Data Exchange (ETDEWEB)
Zen, Heloisa Augusto
2008-07-01
The radiation-induced graft of styrene onto polypropylene (PP) films was carried out by simultaneous irradiation method in a cobalt-60 source. The PP films were immersed in a solution of styrene with toluene (1:1 and 4:1, v/v) under inert atmosphere and at room temperature and then submitted at 20, 40, 80 and 100 kGy. After graft reaction the films were kept at room temperature under inert atmosphere for periods of 7, 14, 21 and 28 days in order to evaluate the degree of grafting. At the end of each period the films were sulfonated to provide the hydrophilic property to PP. The degree of grafting (DOG) was gravimetric determined and the chemical changes in the grafted and sulfonated films were characterized by Infrared Spectroscopy, Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry and the Ion Exchange Capacity (IEC) was calculated. The greatest DOG was obtained after 21 days of post-irradiation. By TGA the grafted films exhibited a decrease in the thermal stability, while the sulfonated exhibited an increase. By DSC was possible to verify that matrix polymeric did not suffer any drastic change in the melting temperature after grafting and sulfonation reactions. The IEC calculated shows that the new membrane developed has ionic conductivity property. (author)
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Energy Technology Data Exchange (ETDEWEB)
Carabe, J
1990-11-01
A study is presented, focused on the preparation and characterisation of hydrogenated amorphous silicon alloy thin films for their application as p type window layers in pin silicon solar cells. The preparation technique used was radio frequency glow discharge. The samples were characterised optically (visible, near infrared and infrared absorption spectrophotometry) and electrically (dark and photoconductivities at ambient temperature and as functions of temperature). The influence of each of the preparation parameters on film properties has been systematically studied. The results have been analysed according to the existing models. Chapter 1 is an introduction to the material in question and its photovoltaic applications. Chapter 2 describes the experimental procedure used. Capter 3 shows and discusses the most relevant results obtained in the study of intrinsic amorphous silicon, p type amorphous silicon and p type amorphous silicon carbide window layers, with special emphasis on the influence of the use of an alternative dopant gas: boron trifluoride. Finally, chapter 4 summarises the most relevant conclusions drawn from this research work. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Brandao, Mauricio O. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE). Programa de Engenharia Mecanica; Giannini, Marcio P.; Arouca, Mauricio C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE). Programa de Planejamento Energetico
2004-07-01
The search for sustainable and more rational means of power generation motivates the scientific crew to search for more efficient and cleaner systems. Oil dependence becomes from the kind of development that the humanity had and cannot be dismissed. The question is how to use this source in a more intelligent way. Fuel Cells are electrochemical devices that convert into electric energy the chemical energy from oxi-reduction reactions between a fuel and an oxidant. The current fuel used in a Fuel Cell is hydrogen and oxygen is the oxidant. The great advantage of this device is its efficiency, higher than the one achieved with internal combustion engines. Also Fuel Cells are not limited by Carnot's efficiency. This paper is about the implementation of a distributed generation system using Fuel Cells. Technical aspects are approached together with economical and environmental needs. The already existence of Gas pipelines and the grown production of Natural Gas presented by Brazil turns it into a good market for the implementation of this energy source. The evaluation of this paper shows that is technically possible to use NG in Fuel Cells, mostly in South and Southeast regions, applying the distributed generation of energy concept. The most interesting in a strategic manner is that Brazil already have an indication that it's capable of developing this technology, opening a new market tuning with world's new technological developments. Many research centers develop this technology, not only from the cell composition itself, but also manufacturing techniques. (author)
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Energy Technology Data Exchange (ETDEWEB)
Kundt, Mirian S; Cabrini, Romulo L [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia
2000-07-01
The evaluation of the degree of development, the number of cells and the DNA content, were used to evaluate the embryotoxicity of uranium. Embryos at a one cell stage were cultured with uranyl nitrate hexahydrate (UN) at a final concentration of uranium (U) of 26, 52 and 104 {mu}gU/ml. At 24 hs of culture, the embryos at the 2 cell stage, were put in new wells with the same concentrations of U as the previous day, until the end of the period of incubation at 72 hs. At 72 hs of culture, 87% of the original one cell embryos were at morula stage, and in those cultivated with uranium, the percentage decreased significantly to 77; 63.24 and 40.79% respectively for the different U concentrations. Those embryos that exhibited a normal morphology, were selected and fixed on slides. The number of cells per embryo was evaluated in Giemsa stained preparations. The DNA content was evaluated cytophotometrically in Feulgen stained nuclei. The number of cells decreased significantly from 20,3 {+-} 5.6 in the control to 19 {+-} 6; 14 {+-} 3 and 13.9 {+-} 5.6 for the different concentrations. All the embryos evaluated showed one easy recognizable polar body, which was used a haploid indicator (n). The content of DNA was measured in a total of 20 control embryos and 16 embryos cultivated with UN. In control embryos, 92,7% of the nuclei presented a normal ploidy from 2n to 4n, 2,9% nuclei were hypoploid and 4,4% were hyperploid. The percentage of hypoploid nuclei rose in a dose-dependent fashion to 3.45; 44.45 and 50.34% respectively for the embryos cultured at the different U concentrations. The results indicate that U is embryotoxic, that its effects are dose dependent at the concentrations used in this study and that even those embryos that show a normal morphology, can be genetically affected. We show that the model employed is extremely sensitive. It is possible to use the preimplantation embryos, as a model to test the effect of possibly mutagenic agents of the nuclear industry. (author)
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Energy Technology Data Exchange (ETDEWEB)
Ellern, Mara; Boccuzzi, Cyro Vicente [ELETROPAULO, Sao Caetano, SP (Brazil)], e-mail: mara.ellern@aes.com; Ett, Gerhard; Saiki, Gerson Yukio; Janolio, Gilberto [ELECTROCELL, Sao Paulo, SP (Brazil); Jardini, Jose Antonio [Universidade de Sao Paulo (USP), SP (Brazil)
2004-07-01
PEM (Proton Exchange Membrane) fuel cell uses a simple chemical reaction to combine hydrogen and oxygen into water, producing electric current in the process. It works something like reversed electrolysis: at the anode, hydrogen molecules give up electrons, forming hydrogen ions (this process is made possible by the platinum catalyst). The proton exchange membrane allows protons to flow through, but not electrons. As a result, the hydrogen ions flow directly through the proton exchange membrane to the cathode, while the electrons flow through an external circuit. As they travel to the cathode through the external circuit, the electrons produce electrical current. At the cathode, the electrons and hydrogen ions combine with oxygen to form water. In a fuel cell, hydrogen's natural tendency to oxidize and form water produces electricity and useful work. No pollution is produced and the only byproducts are water and heat. The huge advance on materials development combined with the growth demand of lower impact on environment is placing the fuel cells on the top of the most promising technologies world-wide. They are becoming in medium term feasible alternatives for energy generators up to energy plants of few MW. (author)
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Energy Technology Data Exchange (ETDEWEB)
Vale, Silvio Bispo do; Bezerra, Ubiratan Holanda; Pinho, Joao Tavares; Pereira, Edinaldo Jose da Silva [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Programa de Pos-Graduacao em Engenharia Eletrica. Grupo de Estudo e Desenvolvimento em Alternativas Energeticas
2004-07-01
This paper presents a case study of a fuel cell (FC) insertion in a small hybrid system for energy generation composed by wind (10 kW), photovoltaic (3,2 kW) and diesel (20 kVA) generations, making computer simulations in order to evaluate the contribution of each one of the energy-supply systems involved. This paper intends to contribute for the establishment of parameters to measure the technical and economic viability for using such isolated hybrid systems, trying in the future several combinations of models to hybridize the energy generation in Amazon isolated villages, making easier the use of local energy resources. (author)
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Energy Technology Data Exchange (ETDEWEB)
Moron, Michelle Mendes
2008-07-01
The basic principle of radiotherapy is the one of maximizing damage to the tumor, while minimizing it in neighboring health tissues. Several strategies have been worked out aiming at increasing cellular radiosensitivity, and among them is the use of exogenous fields. Our goal in this work is the study in human cells of the effect resulting from the association of irradiation with exposure to exogenous static electric fields. The T47D cell line of breast cancer cells was irradiated with gammas in the 0 - 8 Gy doses range. The corresponding survival curve provided information on the radiosensitivity of this cell line. The rate of cell deaths per Gray in the 0 - 8 Gy range exhibited a maximum at 2 Gy, which corresponds to the most efficient irradiation dose. The viability of this T47D cells exposed to both gamma radiation and 1.250 V/cm static electric field (SEF) was about 12% lower than when only irradiated. The sole exposure of the cells to SEF by 24 and 72 hours didn't induce toxicity. Immunofluorescence runs carried out in irradiated normal MRC5 cell line of human lung fibroblast, without and with exposition to a SEF, have quantified the expression of the y- H2AX histone. The amount of phosphorylated histones was approximately 40% higher after irradiation with 2 Gy plus exposure to a SEF by 1 hour, showing that the electric field negatively interfered in the repairing process of the DNA double strand breaks. The flow cytometry analysis with FACS allowed the investigation of a possible interference of radiation and SEF in the cell distributions among the cellular cycle phases. It was found that in T47D cells treated with 1 and 2 Gy by 24 hours the SEF also negatively interfered in the DNA repairing process, as evidenced by the higher accumulation of cells in the S phase. Therefore, it would be possible to conclude that static and exogenous electric fields are able of negatively interfering in the cellular repair and, presumably, in DNA repair. (author)
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Directory of Open Access Journals (Sweden)
Gildásio Cerqueira Daltro
2008-01-01
Full Text Available OBJETIVO: Avaliação da segurança e eficácia do uso de células progenitoras autólogas da medula óssea (CMMO no tratamento da Osteonecrose da Cabeça Femoral (OCF de pacientes portadores de anemia falciforme. MÉTODOS: Foram estudados 8 pacientes portadores de anemia falciforme, com OCF nos estágios I e II (classificação de Ficat e Arlet. As CMMO retiradas da crista ilíaca posterior foram concentradas e reinfundidas na área central da osteonecrose. Os principais parâmetros avaliados foram segurança, sintomas clínicos e progressão da doença, através da avaliação clínica (Harris Hip Score e radiológica. RESULTADOS: A maior parte dos pacientes (7 em 8 referiu melhora dos sintomas após o tratamento. Não houve complicações durante o procedimento anestésico e cirúrgico. A medida do escore (Harris Hip Score no pré-operatório foi 78,5 +/- 6,2 pontos, com aumento significativo destes valores no pós-operatório (98,3 +/- 2,5 pontos (pPURPOSE: To assess the efficacy and safety of autologous bone-marrow mononuclear cells (BMMC implantation in necrotic lesions of the femoral head in patients with sickle cell disease. METHODS: We studied eight patients with stage-I or -II femoral head osteonecrosis according to the system by Ficat and Arlet. BMMCs were harvested and re-infused into the necrotic zone. The primary endpoints studied were safety, clinical symptoms and disease progression, these being assessed according to the Harris hip score (HHS and to X-ray studies. RESULTS: After eight months, seven of the eight patients reported improvement from symptoms. There were no complications during anesthetic and surgery procedures. There was a significant postoperative increase in the HHS (98.3 +/- 2.5 points compared to preoperative HHS (78.5 +/- 6.2 points (p< 0.001. X-ray evaluation and cell parameters were found to be favorable. CONCLUSION: The autologous bone-marrow mononuclear cells implantation seems to be a safe and effective treatment for early stages of femoral head osteonecrosis in patients with sickle cell disease. Although promising, the interpretation of these early results is limited due to the small sample and to the short duration of follow-up. Further studies and advanced cellular assays are required to confirm the results.
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Energy Technology Data Exchange (ETDEWEB)
Forbeck, Guilherme; Folgueras, Marilena V., E-mail: guilhermeforbeck@hotmail.com [Universidade do Estado de Santa Catarina (PGCE/UDESC), SC (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais; Chinelatto, Adilson L. [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Programa de Mestrado em Engenharia e Ciencia dos Materiais
2012-07-01
Titanium dioxide in its polymorphic anatase phase, presents interesting properties for solar cells photo electrodes dye sensitized such as the forbidden energy band, high refractive index and high constant dielectric. In this study, powders of nanometric titanium dioxide were produced with predominantly the anatase phase and high surface area. We used the sol-gel method, and titanium tetraisopropoxide as a precursor, which was hydrolyzed in nitric acid solution. The obtained powder was heated to 450 ° C, varying the time for each lot (0, 20 or 120 minutes). The powders were characterized by X-ray diffraction, atomic force microscopy and surface area analysis. For all lots nanosized crystallites predominated. It was observed that in the batch with 120min heating an increase rutile content. The TiO{sub 2} with 20min heating showed high surface area, greater than that of TiO{sub 2} as taken reference.
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Energy Technology Data Exchange (ETDEWEB)
Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)
2016-07-01
Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)
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Energy Technology Data Exchange (ETDEWEB)
Fiuza, Raigenis da Paz; Souza, Daniele Ribeiro; Barreto, Ednardo Gomes; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)]. E-mail: raigenis@gmail.com
2006-07-01
The PEM (proton exchanging membrane) type fuel cell presents good potential for the energy production without the residue generation. However, its manufacture presents high costs for commercial application, mainly due to the electrolyte. Sulfonated Peek (polish-ether-ether-ketone) supported or auto immobilized the in a silicone matrix is an interesting alternative as electrolyte for PEM fuel cells. The commercial PEEK in powder form was functionalized with sulfuric acid, giving the SPEEK (Sulfonated PEEK). The membranes were produced by hot pressing the SPEEK immobilized in a silicone matrix produced by the sol-gel process. The membranes obtained were characterized by DRX, FTIR, TGA, MEV, DSC and protonic conductivity measurements. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silva, Aline Lima da; Malfatti, Celia de Fraga; Heck, Nestor Cezar [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM)]. E-mail: als14br2000@yahoo.com.br; Mello, Celso Gustavo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Quimica (PPGEQ); Halmenschlager, Cibele Melo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM). Lab. de Materiais Ceramicos
2008-07-01
In SOFC, high operative temperature allows the direct conversion of ethanol into H{sub 2} to take place in the electrochemical cell. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, may occur the breakdown of the electrode. In this way, thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Equilibrium determinations are performed by the Gibbs energy minimization method, using the GRG algorithm. Thermodynamic conditions for carbon deposition were analyzed, in order to establish temperature ranges and H{sub 2}O/ethanol ratios where carbon precipitation is not feasible. A mathematical relationship between Lagrange multipliers and carbon activity is presented, unveiling the carbon activity in atmosphere. The effect of the type of solid electrolyte (O{sup 2-} or H{sup +} conducting) on carbon formation is also investigated. The results of this work are in agreement with previous results reported in literature using the stoichiometric method. (author)
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Energy Technology Data Exchange (ETDEWEB)
Azevedo, Dayse Caldas de; Souza, Adler de; Ferreira, Valdemar Stelita [NovoCell Sistemas de Energia S.A., Santa Barbara D' Oeste, SP (Brazil)]. E-mail: dayse.azevedo@novocell.ind.br
2008-07-01
Fuel cells present the potentiality to substitute the engines of internal combustion in vehicles and to supply energy for stationary use. This potentiality, however, not yet reflected in its introduction in the market with regular lines of production, because of its high cost and lack of criteria that demonstrate its reliability and durability. These subjects are the main goals of the programs of development of fuel cells worldwide. NovoCell is a Brazilian company whose objective is to develop and to produce hydrogen/air fuel cells for stationary generation. All the project is guided by the use of technologies/processes and materials that allow production in large scale and to a competitive cost, giving support to a continuous program of innovation and development of the product. In this work the technological solutions developed by the company are presented. (author)
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Energy Technology Data Exchange (ETDEWEB)
Heusi, Daniel S.; Steidel, Paulo S.; Matelli, Jose A. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Lab. de Combustao e Engenharia de Sistemas Termicos (LabCET); Bazzo, Edson [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)
2004-07-01
Experimental results are presented for a fuel cell type PEM of 15 W. The influence of the operating temperature, as well as the effect of the humidification temperature in the draining of the gases Hydrogen and oxygen, are considered for analysis. The tests were performed at operating temperature in the range of 30 to 70 deg C and humidification temperature form 30 to 85 deg C. For hydrogen flows fixed to be 200 ml/min and 300 ml/min, as well as for oxygen flow of 165 ml/min, the polarization curves were raised taking into account different combinations of operation and different combinations of humidification temperatures. (author)
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Energy Technology Data Exchange (ETDEWEB)
Taylor, J. H. [Departments of Botany and Zoology, Columbia University, New York, NY (United States)
1962-02-15
que deux des constituants de l'ADN etaient repartis d'une maniere semi-reguliere pendant la reproduction. Ces deux constituants presentent certaines differences de structure qui limitent le type des echanges qui peuvent se produire entre les quatre constituants d'un chromosome en voie de reproduction. Les donnees dont on dispose actuellement permettent de supposer que les phases de la reproduction des chromosomes sont regies par des facteurs genetiques. On cherche a obtenir d'autres donnees sur les schemas et sur le mecanisme de controle des phases ainsi que sur d'autres processus connexes qui impliquent la synthese des proteines chromosomiques et de l'autre categorie d'acides nucleiques, les acides ribonucleiques. (author) [Spanish] El tritio constituye el isotopo mas apropiado para alcanzar un elevado poder de resolucion en autorradiografia, por emitir radiaciones beta de baja energia. La relativa abundancia del hidrogeno en la mayoria de las sustancias de importancia biologica, unida al periodo bastante breve del tritio, permiten marcar los componentes de las celulas con actividades especificas que a menudo pueden detectarse en dimensiones de orden intracelular con ayuda de emulsiones nucleares. Las celulas se fijan sobre un vidrio por diferentes procedimientos usados en citobiologia; a continuacion se aplica directamente a su superficie una emulsion fotografica humeda o fluida, que se deja secar. La emulsion se revela despues de la exposicion, cuando todavia se encuentra en contacto con la muestra. Examinando la preparacion (una autorradiografia) al microscopio optico, se pueden apreciar las estructuras celulares y la localizacion del isotopo, con un poder de resolucion inferior a una miera. De este modo, se ha seguido a traves de dos o tres generaciones celulares la distribucion del acido desoxirribonucleico (ADN) tritiado en los distintos cromosomas. Estos estudios pudieron realizarse gracias a la preparacion de timidina tritiada, un marcador muy selectivo del
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Energy Technology Data Exchange (ETDEWEB)
Belchor, P.M. [UFRGS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Berns, B.A.; Ferreira, R.C.; Goldbach, A.; Carpenter, D. [FURB - Fundacao Universidade Regional de Blumenau, Blumenau, SC (Brazil)
2010-07-01
This paper compared the performance of a direct ethanol fuel cell (CCADE) cathode feeding with air replacing the pure oxygen. The results have shown that the small decreasing of the yield of the cell under both practical and experimental situations, by the use of air replacing pure oxygen, it completely acceptable as function of great diminishing of operational costs. (author)
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Energy Technology Data Exchange (ETDEWEB)
Figueroa, P.R.F.; Oliveira, A.A.M. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Combustao e Engenharia de Sistemas Termicos], e-mail: renzo@labcet.ufsc.br, e-mail: amirol@emc.ufsc.br
2006-07-01
The objective of this work is to analyze the ethanol steam reforming for hydrogen production in a compact and modular reforming unit designed for the generation of 1 kw of electrical power. For this, initially the thermodynamic limits for the steam reforming of ethanol are calculated in order to assess the limits in the production of hydrogen and other by-products and to select the best values of process stoichiometry, temperature and pressure for maximum hydrogen selectivity and minimum coke formation. In the following, a First and second Laws analysis is performed to analyze the equilibrium conditions of the main chemical reactions and to estimate the magnitude of the heat transfer required by the heating, evaporation, superheating and reforming of ethanol. Then, the catalytic reformer reactor is analyzed and sized, basing the analysis into the application of the equation for the conservation of mass of the chemical species and a model for the chemical kinetics. A basic reactor design is then proposed accompanied by the corresponding sizes and operating conditions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Garcia-Urrutia, I.; Diez, J. A.; Muller, C.; Calvillo, P.
2009-07-01
Interest in NiW coatings has grown in recent years due to its favourable properties such as hardness, and resistance to both wear and corrosion, making it one of the actual alternatives to hard chromium coatings. In this work, we have undertaken a Hull cell study, investigating the influence of the metal concentration, temperature, pH and current density on the composition of the alloy formed and its thickness. We have also studied the most important properties of the NiW deposits, including morphology, hardness, and resistance to abrasion and corrosion. (Author) 9 refs.
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Energy Technology Data Exchange (ETDEWEB)
Silva, Camila Ramos
2015-07-01
Cancer is considered a public health problem worldwide. According to Brazil's the National Cancer Institute (INCA), 576,000 new cases of cancer were estimated for 2015 in Brazil, representing the second leading cause of death. Radiotherapy may be a treatment to several of types of cancer, frequently using ionizing radiation to eradicate or prevent the proliferation of tumor cells. This treatment, however, can lead to death of non-tumor cells around in irradiated tissue. Given this, adjuvant therapies that can minimize the side effects of ionizing radiation are of extremely importance. In this context, low power laser (LPL) may be an alternative to modulate the response of healthy cells to ionizing radiation. In this study, cells of human gingival fibroblasts (FMM1) and breast cancer (MDAMB- 231) were exposed to gamma radiation at doses of 2.5 and 10 Gy. After twenty-four hours, cell were irradiated with LPL ( λ= 660 nm, 40 mW and total area of 0.04 cm²) with energy densities of 30, 60, 90, 120 and 150 J/cm². The cell viability was measured during four days, using the trypan blue technique. The influence of LPL on the cell cycle and on expression of the nuclear antigen of cellular proliferation (PCNA) was evaluated by flow cytometry. The expression of β-Galactosidase was the chosen method to assess cell senescence. Considering our adopted parameters, and focusing on the non-tumor cells, we have observed an increase in: 1) cell viability; 2) cell population in phases S and G{sub 2}/M cell cycle; 3) PCNA expression with decrease in senescence. No alterations were observed in the cell viability, with greater population in phases S and G{sub 2}/M cell cycle, while the number of senescent cells and the expression of PCNA were decreased. Therefore, we have concluded that the LPL promoted effects on both cell lineages, with increased cell viability on FMM1 cells, whether cancer cells maintained a decreased proliferation. (author)
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Energy Technology Data Exchange (ETDEWEB)
Amendola, Alexandre Gomes; Rocha, Mauro Cesar da [ELETROBRAS, Rio de Janeiro, RJ (Brazil)
2000-07-01
The present work presents a methodology which allows a fast analyses of the economic viability of the implantation of fuel cell power plant. The paper also presents the practical application for two important concessionaires.
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Energy Technology Data Exchange (ETDEWEB)
Santos, Raquel Gouvea dos; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Nucleo de Radiobiologia; Duarte, Rinaldo; Nicoli, Jacques R. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Microbiologia
1996-07-01
The medicine Floratil used for diarrhea treatment is composed by lyophilized yeast cells of Saccharomyces boulardii. The action mechanism of this product is unknown. The efficacy of S. boulardii depends on its viability. The increase in the trehalose level in S. cerevisiae cells submitted to a previous sub-lethal level heat shock results in resistance to a lethal shock. The aim of this work was to study weather the cell trehalose level is involved also in the resistance of gamma irradiation. It was noted that the yeast cells surviving to gamma irradiation had more trehalose level than control cells. Apparently there is a positive correlation between of trehalose level and gamma irradiation resistance of S.boulardii cells. (author)
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Energy Technology Data Exchange (ETDEWEB)
Barreto, Ednardo G.; Fiuza, Raildo A.; Catao, Ronei S.; Jose, Nadia M.; Boaventura, Jaime S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: ednardobarreto@yahoo.com.br, e-mail: raildofiuza@gmail.com, e-mail: roneicatao@ig.com.br, e-mail: nadia@ufba.br, e-mail: bventura@ufba.br; Pepe, Yuri [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Fisica
2007-07-01
This work had the objective to develop and to characterize S-PEEK membranes (sulfonated poly ether ether ketone) through chemical and electrochemical analyses. Conductivity test in function of the frequency and tension had been carried through; as well as, the open circuit tension of a fuel cell using the S-PEEK as electrolyte. Additional tests included TGA (Thermogravimetric Analysis), water absorption test, DSC (Differential Scanning Calorimetry), as tools to characterize conducting, thermal and mechanical proprieties of polymeric membrane. (author)
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Monica Leal Alcure
2006-01-01
Resumo: As infecções superficiais e sistêmicas provocadas por Candida são freqüentes causas de morbidade e mortalidade em pacientes submetidos a transplante de células progenitoras hematopoiéticas (TCPH). Entre os fatores de risco destaca-se a colonização prévia a qual parece ser um pré-requisito para o desenvolvimento de infecção. Desta forma, a cavidade oral pode atuar como um reservatório para esses microorganismos. O presente estudo teve como objetivo avaliar, prospectivamente, o fluxo sa...
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Energy Technology Data Exchange (ETDEWEB)
Oliveira, R.L.B.C. de
1981-12-31
The heat sterilization of reducing sugars, in the presence of phosphates, in alkaline pH, promotes caramelization reactions, yielding a serie of degradation products. Among them, aldehyde-like compounds seem to be responsible for the decrease in viability of DNA repair-proficient E.coli cells. A positive interaction between toxic solutions and UV-radiation effects is observed in these cells. The sinergism UV-toxic solutions varies in function of post-irradiation time and is dependent on UV dose, indicating the interference of repair processes in toxicity. The effect of non-reducing sugars on cellular viability is negligible, suggesting that toxic substances generation is linked to the presence of at least a free carbonyl group in sugar structure. All tested reducing sugars, when experimental conditions remained constant, have similarly shaped inactivation kinetics and their effects are equally inhibited by catalase activity, during incubation. (author).
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Biofunctionality and immunocompatibility of starch-based biomaterials
Marques, Alexandra Margarida Pinto
inflamatoria a biomateriais. Em resumo, os estudos de citocompatibilidade e imunocompatibilidade demonstraram que os polimeros e compositos a base de milho sao biomateriais promissores. Em comparacao com os biomateriais degradaveis actualmente em uso, possuem propriedades capazes de induzir um comportamento semelhante, ou mesmo melhor, em termos de citotoxicidade. Estes dados foram reconfirmados com a adesao e proliferacao de celulas do tipo osteoblastos na superficie de alguns dos materiais a base de amido, que demonstraram ser comparaveis as observadas no PLLA, evidenciando a possibilidade de usar esses materiais em aplicacoes ortopedicas. As conclusoes retiradas dos estudos in vitro e in vivo de imunocompatibilidade reforcam as observacoes das experiencias de citocompatibilidade e em conjunto, evidenciam a possibilidade de utilizacao dos biomateriais a base de amido, com fraca capacidade de desencadear uma reaccao inflamatoria, em aplicacoes biomedicas. (Abstract shortened by ProQuest.).
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Energy Technology Data Exchange (ETDEWEB)
Marcano, Letty; Carruyo, Ingrid; Montiel, Xiomara [Univ. del Zulia, Facultad Experimental de Ciencias, Dept. de Biologia (Venezuela); com, letty_marcano@hotmail; Faria, Clarisa de R [Univ. del Zulia, Facultad de Medicina, Catedra de Histologia, Maracaibo, Zulia (Venezuela)
2006-06-15
microscopia electronica de transmision. Se identifico cambios fenotipicos (diferencias entre talla y peso) y fisiologicos (debilidad muscular e intranquilidad); a nivel histologico, perdida de la disposicion trabecular y de la arquitectura lobulillar, focos de aglomerados linfociticos, vacuolizacion, dilatacion de sinosoides y de la vena central, entre otros. El estudio ultraestructural senala diversas alteraciones tales como: nucleolo con un elevado numero de centros fibrilares (50 ppm); voluminosas gotas de lipidos en el citoplasma, reticulo endoplasmatico rugoso distendido, vacuolizacion citoplasmatica, lisosomas y peroxisomas alterados (100 ppm); nucleos contraidos con cromatina condensada, dilatacion en el espacio intracelular y areas de perdida mitocondrial y fibrilar (150 ppm). Se sugiere que el cadmio ejerce un efecto toxico en las celulas hepaticas el cual se hace mas severo con el aumento de la concentracion, llevando a la necrosis celular. (autor)
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Directory of Open Access Journals (Sweden)
Geovana Dotta
2011-07-01
alimentacao foi injetado carragenina ou salina. Apos 6h, realizou-se a coleta de exsudato e sangue para determinacao do hematocrito, contagens totais de eritrocitos, leucocitos, contagem diferencial de leucocitos e atividade fagocitaria no sangue. A suplementacao com probiotico na racao nao influenciou o numero total de eritrocitos, o hematocrito e os numeros de linfocitos e basofilos no sangue dos animais. O numero de neutrofilos foi maior nos peixes suplementados com probiotico einjetados com carragenina. A glicose nos peixes suplementados com probiotico nao-injetados foi maior do que nos injetados com salina. A suplementacao com probiotico potencializou a migracao de celulas para o foco inflamatorio nos injetados com o flogogeno carragenina. Empeixes injetados com salina e carragenina, ocorreu maior atividade fagocitaria no sangue em relacao aos demais tratamentos.
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Directory of Open Access Journals (Sweden)
Paulo Roberto Ceridóreo Corrêa
2011-09-01
Full Text Available The effect of 2-pyridinecarboxylic acid (picolinic acid on trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus was determined in this study. Picolinic acid, at 50 ƒÊg mL-1, inhibited epimastigote growth by 99% after 12 days incubation. In addition, trypomastigote motility decreased by 50% after 6h and completely after 24h in the presence of 50 ƒÊg mL-1 picolinic acid. The 50% cytotoxic concentration on HEp-2 cell line was275 ƒÊg mL-1 after 4 days incubation. Altogether, these results indicate higher toxicity against trypanosomes. The inhibitory effect of picolinic acid on epimastigote growth can be partially reversed by nicotinic acid and L-tryptophan, suggesting a competitive inhibition. Furthermore, two anti-Trypanosoma (Schizotrypanum cruzi drugs were also evaluated with regard to bat trypanosome growth. Benznidazole, at 50 ƒÊg mL-1, inhibited epimastigote growth by 90% after 12 days incubation. Nifurtimox, at the same concentration, caused 96% growth inhibition after four days incubation. Corroborating a previous study, bat trypanosomes are a good model for screening new trypanocidal compounds. Moreover, they can be used to study many biological processes common to human pathogenic trypanosomatids.O efeito do acido 2- piridinocarboxilico (acido picolinico sobre um tripanossoma do subgenero Schizotrypanum isolado do morcego Phyllostomus hastatus foi determinado neste estudo. O acido picolinico, na concentracao de 50 ƒÊg mL-1, inibiu 99% do crescimento de epimastigotas apos 12 dias de incubacao. Alem disso, houve um decrescimo de 50 e 100% na mobilidade dos tripomastigotas apos 6 e 24h, respectivamente, em presenca de acido picolinico na concentracao de 50 ƒÊg mL-1. A concentracao citotoxica 50% para celulas HEp-2 foi de 275 ƒÊg mL-1 apos quatro dias de incubacao. Esses resultados indicam maior toxicidade contra os tripanossomas. O efeito inibitoriodo acido picolinico sobre o crescimento de
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Energy Technology Data Exchange (ETDEWEB)
Souza, Antonio Carlos Caetano de; Gallo, Giulliano Batelochi; Silveira, Jose Luz [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia], e-mail: caetano@feg.unesp.br
2004-07-01
In this paper a hybrid solid oxide fuel cell (SOFC) system, applying a combined cycle using gas turbine for rational decentralized energy production is analyzed. The relative concepts about the fuel cell are presented, followed by some chemical and technical information such as the change of Gibbs free energy in isothermal fuel oxidation directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC and gas turbine system is developed, considering the electricity and steam production for a hospital. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. A Sankey Diagram shows that the hybrid SOFC system is a good opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a good technical alternative, demanding special methods of design, equipment selection and contractual deals associated to electricity and fuel supply. (author)
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Energy Technology Data Exchange (ETDEWEB)
Canteli Perez-Caballero, D.
2015-07-01
Transparent conductive oxides (TCOs) are heavily doped oxides with high transparency in the visible range of the spectrum and a very low sheet resistance, making them very attractive for applications in optoelectronic devices. TCOs are widely found in many different areas such as low emissivity windows, electric contacts in computers, televisions or portable devices, and, specially, in the photovoltaic (PV) industry. PV industry is mainly based on mono- and multicrystalline silicon, where TCOs are used as anti-reflective coatings, but the search for cheaper, alternative technologies has led to the development of thin film PV technologies, where TCOs are used as transparent contacts. With the maturation of the thin film PV industry, laser sources have become an essential tool, allowing the improvement of some industrial processes and the development of new ones. Because of the interest on a deeper understanding of the interaction processes between laser light and TCOs, the laser ablation of three of the most important TCOs has been studied in depth in the present work. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Marin Neto, Antonio Jose; Silva, Ennio Peres da; Camargo, Joao Carlos; Neves Junior, Newton Pimenta; Pinto, Cristiano da Silva [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Lab. de Hidrogenio; Pinto, Cristiano da Silva [Centro Nacional de Referencia em Energia do Hidrogenio, Campinas, SP (Brazil)
2004-07-01
This paper describes preliminary results obtained with the allothermal ethanol reforming system for synthesis gas (syn-gas) production and hydrogen upgrading and purification for fuel cell applications. The system was designed to supply hydrogen to a 500 W PEM (Proton Exchange Membrane) fuel cell, with an electrical efficiency of 45%, which requires approximately 0.45 m3.h-1 of hydrogen, with a maximum carbon monoxide concentration of 20 {mu}mol.mol-1 (ppm). The study was performed changing the operation temperature and analyzing the resulting syn-gas through gas chromatography for a specific catalyst. This catalyst was tested up to 700 deg C, 1 bar and fixed stoichiometric steam to carbon ratio. The syn-gas, before carbon monoxide shift reactor implementation, was submitted to a two-bed-three-segments purification step composed of chemical and physical molecular sieves for hydrogen purification. The carbon monoxide shift reactor (water gas shift reactor) is under development to improve the efficiency-to-hydrogen and maximize the life of the purification bed. The final results also include a discussion about possible reactions involved in ethanol steam-reforming for such catalyst. (author)
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Energy Technology Data Exchange (ETDEWEB)
Andrighetto, Daniela; Dornelles, Eduardo Bortoluzzi; Cruz, Ivana Beatrice Manica da; Lüdke, Everton, E-mail: daniela.andrighetto@hotmail.com, E-mail: dornellesedu@gmail.com, E-mail: ibmcruz@hotmail.com, E-mail: evertonludke@gmail.com [Universidade Federal de Santa Maria (UFSM), RS (BRazil)
2014-07-01
The goal of this study is to develop an in vitro irradiation cell system with controllable irradiation intensities of 27 MHz produced by an argon plasma column with variable amplitude modulation in the 100-700 kHz range. This paper presents and discusses a proposed experiment, with toxicity analysis (DNA Picogreen®) and cell viability (MTT assay) in the radiation-induced HT-29 cell line (colon adenocarcinoma). The data allow us to observe that cellular toxicity effects may occur with exposure to fields produced by argon plasma with intensities on the order of at least 3.2 W / cm2 and exposure times above 3.5 hours continuously. An analysis of cell populations for cell toxicity tests using the Student's t-test did not show significant changes (p <0.05) in the amount of DNA released by the action of radiofrequency, although it has been found that cell viability (MTT) is not significantly altered by long exposures to radiation induced plasma RF signals in 27 MHz (p> 0.34). Cytotoxic effects due to the destruction of cell wall by heating the samples were not detected in any of the tests.
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Kolotygin, Vladislav
This work was focused on the analysis of transport, thermomechanical and electrochemical properties of a series of perovskite-like oxide materials and composites for potential applications as anodes of intermediate-temperature solid oxide fuel cells (SOFCs) with lanthanum gallate and silicate solid electrolytes. The primary attention was centered on A(Mn,Nb)O3-delta (A = Sr, Ca) and (La,Sr)(Mn,Ti)O3-based systems, lanthanum chromite substituted with acceptor-type and variable-valence cations, and various Ni-containing cermets. Emphasis was given to phase stability of the materials, their crystal structure, microstructure of porous electrode layers and dense ceramics, electronic conductivity, Seebeck coefficient, oxygen permeability, thermal and chemical induced expansion, and anodic overpotentials of the electrodes deposited onto (La,Sr)(Ga,Mg)O3- and La10(Si,Al)6O27-based electrolyte membranes. In selected cases, roles of oxygen diffusivity, states of the transition metal cations relevant for the electronic transport, catalytically active additives and doped ceria protective interlayers introduced in the model electrochemical cells were assessed. The correlations between transport properties of the electrode materials and electrochemical behavior of porous electrodes showed that the principal factors governing anode performance include, in particular, electronic conduction of the anode compositions and cation interdiffusion between the electrodes and solid electrolytes. The latter is critically important for the silicatebased electrolyte membranes, leading to substantially worse anode properties compared to the electrochemical cells with lanthanum gallate solid electrolyte. The results made it possible to select several anode compositions exhibiting lower area-specific electrode resistivity compared to known analogues, such as (La,Sr)(Cr,Mn)O3-delta.
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Energy Technology Data Exchange (ETDEWEB)
Attab, Cyomara Sanches, E-mail: rubinha.attab@terra.com.b [Centro Brasileiro de Medicina Nuclear (CEBRAMEN), Goiania, GO (Brazil); Moriguchi, Sonia Marta [Fundacao Pio XII, Barretos, SP (Brazil). Hospital de Cancer; Paton, Eduardo Jose Alencar [Fundacao Pio XII, Barretos, SP (Brazil). Cancer Hospital. Div. of Hemotherapy and Bone-Marrow Transplant; Alencar, Mario Henrique Leite de [Clinica de Prevencao em Cancer, Goiania, GO, (Brazil); Rocha, Euclides Timoteo da [Fundacao Pio XII, Barretos, SP (Brazil). Cancer Hospital. Dept. of Nuclear Medicine
2010-05-15
The authors describe two cases of cutaneous B-cell lymphoma where correct staging, treatment and follow-up could be achieved through a combination of conventional imaging studies and gallium-67 scintigraphy. (author)
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Directory of Open Access Journals (Sweden)
Shirley Martins
2008-06-01
Full Text Available Foram analisados aspectos anatômicos e ultra-estruturais foliares de Cyperus maritimus Poir. visando identificar caracteres adaptativos ao ambiente de dunas litorâneas. Para isto, indivíduos ocorrentes nas dunas da Praia de Pipa, Rio Grande do Norte, Brasil, tiveram as folhas submetidas a diferentes análises: microscopia de luz, eletrônica de varredura e de transmissão. Em vista frontal, a epiderme possui tricomas unicelulares, corpos de sílica, cutícula estriada e depósitos de cera. Em secção transversal, a epiderme é unisseriada com parede periclinal externa espessa. Os estômatos são paracíticos, podendo o ostíolo estar obstruído por cera. Abaixo da face adaxial observa-se o parênquima aqüífero. Os feixes vasculares ocorrem em múltiplas fileiras, sendo as periféricas compostas por feixes de diâmetro menor que os feixes da fileira central. Foram observados caracteres relacionados à síndrome Kranz do tipo clorociperóide. Aspectos ultra-estruturais, como cloroplastos presentes na bainha do feixe, esses sem grana evidentes, entre outras características, reforçam a possível ocorrência da via C4 nesta espécie. É a primeira citação para o gênero Cyperus de cloroplasto nas celulas do tecido vascular. Neste trabalho foi possível observar vários caracteres importantes para plantas submetidas a estresse hídrico e salino, como: cera, células epidérmicas com parede periclinal externa espessada, parênquima aqüífero e síndrome Kranz.Anatomical and ultrastructural aspects of Cyperus maritimus Poir. were analyzed with the aim of identifying adaptive features for the dune environment. Collections were made at Pipa beach, Rio Grande do Norte, Brazil. Leaves were submitted to different analyses: light microscopy, scanning and transmission electron microscopy. In frontal view, the epidermis has unicellular trichomes, silica bodies, a striate cuticle and wax deposits. In transverse section, the epidermis is uniseriate
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Energy Technology Data Exchange (ETDEWEB)
Nobrega, Shayenne Diniz da; Vasconcelos, Carmel Suzarte Ayres; Lima, Luiz Rogerio Pinho de Andrade [Universidade Federal da Bahia (UFBa), Salvador, BA (Brazil). Escola Politecnica. Dept. de Ciencia e Tecnologia dos Materiais]. E-mail: shayennedn@yahoo.com.br
2008-07-01
Fuel cell is an electrochemical device that converts the chemical energy into electric energy. The natural gas, for its proven improvement in the income of the equipment in relation to other energy ones, has been very used to feed the solid oxide fuel cell (SOFC) in the generation of electric power. Ceramics of Yttria-stabilized zirconia had been used as electrolyte and when supported with nickel oxide they act as anode in the solid oxide fuel cell, due to raised ionic conductivity that these materials present in high temperatures, while lanthanum with strontium and manganite are used as cathode. In the composition of the anode, the concentration of Ni O, acting as catalytic in the YSZ confers high electric conductivity and high electrochemical activity of the reactions, providing the internal reform in the SOFC. In this work, the solid oxide fuel cell, formed by Yttria- stabilized zirconia, nickel oxide, and lanthanum with strontium and manganite were tested in the reform had been prepared samples of electrode/electrolyte for use in SOFC of the natural gas in the presence of low water text, similar condition to the operation of the SOFC, operating in temperatures range from 700 to 800 deg C. This cell also was characterized using the impedance spectroscopy technique. These results allowed the development of components of the current versus voltage. (author)
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Energy Technology Data Exchange (ETDEWEB)
Santos, Rubens Souza dos [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Martinez, Aquilino Senra; Alvim, Antonio Carlos Marques [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear
2002-07-01
In this work is presented a methodology which focuses the distribution of neutron absorber rods in nuclear reactor power plants, for utilizing in space kinetic calculations, principally in the cluster ejection transients of control rods. A numerical model for macroscopic constant calculations based on the knowledge of the neutron flux without the control rods is proposed, as alternative to the analytical models, based on the hypothesis of the null current on the cell super boundaries. The proposed model in this work has itself showed adequate to deal with problems with strong space dependence, once that the model showed consistence in the global average built in the analytical model. (author)
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GATICA GUTIERREZ, RODRIGO ORLANDO; GATICA GUTIERREZ, RODRIGO ORLANDO
2012-01-01
En el presente estudio se determinó los efectos sobre la expresión y localización del receptor de insulina (InsR), de glicógeno sin tasa (GS) y de las enzimas glicolíticas y gluconeogénicas en diabetes de largo plazo. Insulina es esencial para el manejo energético del cuerpo, sin embargo, su rol a nivel renal es poco conocido. Su unión al receptor de insulina provoca una cascada de señalización intracelular, que regula múltiples procesos biológicos, tales corno el metabolismo lipídico y pr...
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Energy Technology Data Exchange (ETDEWEB)
Almeida, G.R.S de; Fagury Neto, E.; Rabelo, A.A., E-mail: grs_gustavo@hotmail.co [Universidade Federal do Para (UFPA), Maraba, PA (Brazil). Fac. de Engenharia de Materiais
2010-07-01
From the pursuit of lower operating temperature of fuel cells solid oxide was used polymeric precursor for the synthesis of reactive powder compositions Zr{sub 0,92}Y{sub 0,08}O{sub 2} for the anode and Ce{sub 0,88}Ca{sub 0,12}O{sub 2} for the electrolyte. The solutions were prepared using the metal in much of the composition and citric acid molar ratio of 1:3, under stirring at 60 deg C/1 h. The mixture of metallic citrates was subjected to agitation at a temperature of 80 deg C which was added ethylene glycol in the ratio 60:40 by weight citric acid / ethylene glycol, to form a resin that was pre-calcined at 300 deg C/3 h for to form the expanded resin. The powders were disaggregated in a mortar, screened and calcined at 400, 600 and 800 deg C/2 h. The powders were characterized by standard X-ray diffraction. (author)
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Energy Technology Data Exchange (ETDEWEB)
Moreno B, R
2004-07-01
The chlorophyllin (CHLN) is a porphyrin of nutritious grade and soluble in water, derived of the chlorophyll. It has been reported that this pigment is a good anti mutagen since it reduces the damage to the DNA caused by physical or chemical agents of direct or indirect action. Their anti carcinogenic action has also been demonstrated when it is administered itself during the induced post-initiation phase by aflatoxins and heterocyclic amines. However in the last decade it has been reported that it also has promoter activity against the genetic damage induced by diverse agents like the alkyl ants of direct and indirect action, the gamma radiation and some heterocyclic amines. This effect has been observed in testing systems like Salmonella, Drosophila, rainbow trout and rodents. In the mouse spermatogonia it has been reported that it reduces the damage to the DNA but with the test of lethal dominant in Drosophila increment the damage induced by gamma radiation. The present study consisted on evaluating the effect of the CHLN in the line germinal masculine of Drosophila by means of the lethal recessive test bound to the sex (LRLS) with the stump Muller 5 and a litters system. Its were pretreated wild males with CHLN and 24 h later were irradiated with 0, 10, 20 and 40 Gy of gamma radiation immediately later were crossed with virgin females of the stump Basc and at 72 h the male was transferred to a cultivation media with three new virgin females, this process repeated three times until completing 3 litters. The F1 it was crossed among itself and in the F2 it was analysed the presence or absence of lethals. The results indicated that the CHLN per se incremented the basal frequency of damage due to the pigment can act as an agent that is inserted to the ADN causing pre mutagenic leisure. Nevertheless with the groups treated with the different doses of gamma radiation the CHLN does not present any protector action, neither promoter except in the litter I of the group treated with 20 Gy where it was observed a promoter effect of genetic damage. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Cervantes Jaramillo, Enrique L.; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)
1996-12-31
% de su capacidad, lo que conlleva la desaparicion de buena parte de la carga puramente resistiva del usuario; lo cual ocasionara que su factor de potencia natural sea disminuido de 0.91 a 0.86 atrasado. c) Al disminuirse la demanda maxima anual del circuito de distribucion en una proporcion mayor que la disminucion de su consumo anual, sus factores de carga y de perdidas anuales se veran incrementados y por consiguiente; en proporcion, sus perdidas anuales de energia se veran incrementadas en un 18.9%. Lo anterior, da origen a que la compensacion de la potencia reactiva mediante la instalacion de bancos de capacitores en la troncal del circuito de distribucion, sea una solucion tecnico-economica altamente atractiva, con una relacion beneficio/costo de 4, un tiempo de retorno de la inversion de 2 anos y un Beneficio Neto de $4.78/usuario.
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Energy Technology Data Exchange (ETDEWEB)
Cervantes Jaramillo, Enrique L; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)
1997-12-31
% de su capacidad, lo que conlleva la desaparicion de buena parte de la carga puramente resistiva del usuario; lo cual ocasionara que su factor de potencia natural sea disminuido de 0.91 a 0.86 atrasado. c) Al disminuirse la demanda maxima anual del circuito de distribucion en una proporcion mayor que la disminucion de su consumo anual, sus factores de carga y de perdidas anuales se veran incrementados y por consiguiente; en proporcion, sus perdidas anuales de energia se veran incrementadas en un 18.9%. Lo anterior, da origen a que la compensacion de la potencia reactiva mediante la instalacion de bancos de capacitores en la troncal del circuito de distribucion, sea una solucion tecnico-economica altamente atractiva, con una relacion beneficio/costo de 4, un tiempo de retorno de la inversion de 2 anos y un Beneficio Neto de $4.78/usuario.
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Directory of Open Access Journals (Sweden)
Josefa Larrán López
2004-06-01
Full Text Available La importancia de realizar un diagnóstico sobre la situación inicial de los alumnos que comienzan un nuevo curso es de sobras conocida. Los resultados del proceso de enseñanza-aprendizaje dependen en gran medida del estado inicial de preparación y motivaciones de los alumnos. Por tanto, la identificación de factores que se relacionen con el rendimiento académico es un tema a tener en cuenta en el proceso de mejora de la calidad de la enseñanza universitaria. En el presente trabajo presentamos datos obtenidos a partir de la evaluación inicial realizada a los alumnos de la asignatura troncal Biología Celular y Tisular Humana de primer curso de la Diplomatura en Fisioterapia. Como instrumento utilizamos un cuestionario de respuesta abierta que nos proporciona información sobre distintas variables como: sexo, modalidad de acceso a la Universidad, motivaciones, aspiraciones, conocimientos previos relacionados con la asignatura, etc. Presentamos, igualmente, la calificación final obtenida por los alumnos (evaluación sumativa. Realizamos un análisis descriptivo de las variables iniciales, relacionándolas entre sí y con las calificaciones finales con objeto de identificar factores indicadores del rendimiento académico. Entre los resultados obtenidos observamos que los conocimientos previos relacionados con la asignatura son, en general, insuficientes y/o confusos, observándose una mejor preparación previa en los alumnos procedentes de COU/Bachillerato con respecto a los de Formación Profesional. Entre las variables analizadas son estos conocimientos previos los que muestran una relación estadísticamente significativa y directamente proporcional con las calificaciones finales.The importance of evaluating prior academic knowledge possessed by students beginning a new course is well known. The results of the teaching-learning process depend to a large extent on students’ previous level of instruction and motivation. Therefore
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Energy Technology Data Exchange (ETDEWEB)
Oliveira, Sergio Pinheiro de; Trota Filho, Jorge; Couto, Paulo Roberto Guimaraes; Rocha, Adriana da Cunha [Instituto Nacional de Metrologia Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias, RJ (Brazil)]. E-mail: spoliveira@inmetro.gov.br
2008-07-01
This work presents and compares the results obtained from the assessment of the uncertainty of measurement of the energetic efficiency calculations of a PEM unit fuel cell and from the total electrical power of a PEM fuel cell stack. This assessment makes use of three different methods of calculation: the Classical method and the Kragten method, both described in the ISO GUM 95 'Guide to the expression of uncertainty in measurement' and the Monte Carlo method, described in the Supplement 1 to the ISO GUM 95. Concerning the energetic efficiency, both the Classical and Kragten methods presented the same uncertainty values, 0.00029 whereas the Monte Carlo method presented a value of 0.00021. The difference between these two values (0.8 x 10{sup -5}) was greater than the {delta} criteria tolerance established in the Supplement 1 (0.5 x 10{sup -5}). This fact though, has not invalidated the results of the ISO GUM 95, as this work focused on the conservative value of the uncertainty. With respect to the uncertainty of the total electrical power of the fuel cell stack it has been observed that the main contribution for the uncertainty calculation, i.e., the higher uncertainty source (92.8%), was given by the accuracy class of the multimeter employed in the measurements. Additionally to the comparative study of the methods for the uncertainty calculations, this work establishes the correct accuracy class of a multimeter used for the measurement of the given/consumed electric potential by a fuel cell stack, aiming the cost/benefit relation of the process. (author)
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Energy Technology Data Exchange (ETDEWEB)
Blanco, Lyzed Toloza; Loureiro, Felipe A.M.; Rocco, Ana Maria [Grupo de Materiais Condutores e Energia, Escola de Quimica, Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)], e-mail: amrocco@eq.ufrj.br; Pereira, Robson Pacheco [Instituto de Ciencias Exatas, Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil)
2011-07-01
In the present work, the synthesis and characterization of sulfonic membranes based on interpenetrating polymer networks (IPN). In order to obtain such systems, the diglycidyl ether of bisphenol A (DGEBA) was polymerized in presence of polyethyleneimine (PEI). These membranes were submitted to sulfonation reactions, originating IPN-SO{sub 3}H membranes. The characterization by FTIR evidenced the formation of a Semi-IPN structure, while sulfonation reactions resulted in systems containing -SO{sub 3}H groups covalently bonded to the chains. The membranes exhibited water retention up to 200 degree C, in a temperature range sufficient for application in PEMFC under hydration. (author)
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Energy Technology Data Exchange (ETDEWEB)
Marcolino, Juliane Bernardes
2011-01-15
Photovoltaics is based on the direct conversion of solar energy into electricity and is a promising alternative to diversify the world's energy matrix. This work aims to develop and analyse the deposition of Al paste by screen printing and firing/diffusion in a belt furnace to produce a BSF region in monocrystalline Si wafers. The diffusion of Al into the substrate was implemented by two different processes. In the first process the diffusion/firing of the Al paste and the firing of the Ag paste was carried out in independent steps. In this case, solar cells with an average efficiency ({eta}{sub average}) of 11.5 % and a maximum of 12.0 % were produced, but with the formation Al clusters in the back surface of the devices. In the second process firing/diffusion of such pastes was done on the same step. In this case, the best results were obtained for a firing/diffusion temperature of 860 deg C and belt furnace speed (V{sub E}) of 150 cm/min and also for 890 deg C and 180 cm/min. For the former parameters, {eta}{sub average} was 12.4 % and the maximum was 12.8 %. For the later, {eta}{sub average} was 12.5 % and the maximum was 12.6 %. Considering a temperature of 900 deg C and V{sub E} of 190 cm/min, {eta}{sub average} was 12.4 %. It was observed that minority carriers diffusion lengths were smaller than the thickness of silicon wafers. Open circuit voltages were 30 mV lower than that from similar cells fabricated at NT-Solar by using high purity Al deposited by e-beam evaporation indicating that the developed process produced low quality BSF. (author)
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Energy Technology Data Exchange (ETDEWEB)
Santos, J.N.; Kunsti, S.R.; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul - Departamento de Metalurgia (PPGEM) - Laboratorio de Pesquisa em Corrosao (LAPEC), Porto Alegre, RS (Brazil); Vargas, J.V.C. [Universidade Federal do Parana - Departamento de Engenharia Mecanica, PR (Brazil); Amico, S.C. [Universidade Federal do Rio Grande do Sul - Departamento de Materiais, RS (Brazil)
2010-07-01
The electrode/membrane system, called MEA, is the fundamental unit of a PEMFC (proton exchange membrane fuel cell). Within the MEA, the gas diffusion layer (GDL) is the bridge between the flow field and the catalyst layer. One of the important elements in a GDL is the substrate, typically a carbon cloth or paper, that has to be an excellent electrical conductor and show mechanical strength along with thermal and chemical stability. In this work, GDLs were produced from a suspension containing short carbon fibers in water-based polyurethane and poly(vinyl alcohol) (PVA) resins with appropriate characteristics to be used in low temperature fuel cells. The obtained GDL was characterized regarding its wettability, electrical conductivity and morphological aspects, evaluated by SEM. (author)
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Energy Technology Data Exchange (ETDEWEB)
Balenzategui Manzanares, J. L.
2005-07-01
Photon recycling (PR) is the process by which photons internally emitted in a semiconductor can be re-absorbed by the material, giving as result new electron-hole pairs. Although this process has been receiving some international research from the Sixties, because their effects revealed as relevant in certain devices and materials (as in gallium arsenide), its influence in the operation of solar cells has been scarcely considered in the past. Thus deposited it has been demonstrated that one of its major effects is an enhancement of the radiative carrier lifetine, photon recycling is not usually taken into account in photovoltaic, neither in device modelling and simulation, nor from the perspective of taking advantage of the phenomenon to improve the efficiency of solar cells. This work describes the results of our investigations in the field of photon recycling. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Brueggemann, J.; Giesecke, D. [Institute of Physiology and Animal Nutrition, University of Munich, Munich, Federal Republic of Germany (Germany)
1962-02-15
de los bovinos. Las dosis de hasta 150 krad (cinco dias) no ejercieron un efecto acentuado sobre la proliferacion anaerobia ni sobre el metabolismo de los carbohidratos. En cambio, si la irradiacion de las celulas en reposo se efectua en presencia de oxigeno se observa una notable disminucion del numero de celulas viables. Se ha comprobado que el oxigeno ejerce per se un efecto letal en estas Bullet especies, que decrece logaritmicamente. Se supone que los productos de irradiacion secundarios, sobre todo el H{sub 2}O{sub 2}, son los principales causantes del efecto del T{sub 2}O en estos microorganismos que carecen de catalasa. Los autores esperan obtener algunos resultados confirmatorios. (author) [Russian] Bakterial'naja flora zhvachki krupnogo rogatogo skota sostoit v osnovnom iz chisto anajerobnyh bakterij, kotorye snabzhajut zhivotnoe bol'shim kolichestvom letuchih zhirnyh kislot (LZhK) kak osnovnogo iotochnika jenergii. Dlitel'noe obluchenie flory v laboratornyh uslovijah posred- stvom T{sub 2}O pri tak nazyvaemom 'iskusstvennom perezhevyvanii' v anajerobnyh uslovijah pokazalo, chto dozy do 75 Krad ne imejut sderzhivajushhego vlijanija na rost bakterij i vyrabotku LZhK. Stimuliruemye vozdejstvija, zakanchivavshiesja uskoreniem delenija kletki, i vozrosshie kolichestva LZhK nabljudalis' posle obluchenija nahodjashhejsja v svo- bodnom sostojanii flory pri 0 Degree-Sign C v obshhej doze okolo 30 Krad cherez 20 dnej, no vosproizvodstvo bylo neudovletvoritel'nym vsledstvie geterogennosti veshhestva. Dal'nejshie jeksperimenty osushhestvljalis' na chistyh kul'turah otobrannyh porod bakterij zhvachki. Dozy do 150 Krad (5 dnej) ne okazali zametnogo vli- janija na anajerobnyj rost i metabolizm uglevoda. Odnako, esli pri obluchenii nahodjashhihsja v svobodnom sostojanii kletok prisutstvoval kislorod, otmechalos' znachitel'noe sokrashhenie zhiznesposobnyh kletok. Byl obnaruzhen kislorod, koto- ryj na jetot vid bakterij okazyvaet letal'noe dejstvie, soprovozhdavsheesja
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Energy Technology Data Exchange (ETDEWEB)
Miyaki, Liza Aya Mabuchi [Faculdade de Enfermagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Sibov, Tatiana Tais; Pavon, Lorena Favaro; Mamani, Javier Bustamante; Gamarra, Lionel Fernel, E-mail: tatianats@einstein.br [Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil)
2012-04-15
Objective: To analyze multimodal magnetic nanoparticles-Rhodamine B in culture media for cell labeling, and to establish a study of multimodal magnetic nanoparticles-Rhodamine B detection at labeled cells evaluating they viability at concentrations of 10 {mu}g Fe/mL and 100{mu}g Fe/mL. Methods: We performed the analysis of stability of multimodal magnetic nanoparticles-Rhodamine B in different culture media; the mesenchymal stem cells labeling with multimodal magnetic nanoparticles-Rhodamine B; the intracellular detection of multimodal magnetic nanoparticles-Rhodamine B in mesenchymal stem cells, and assessment of the viability of labeled cells by kinetic proliferation. Results: The stability analysis showed that multimodal magnetic nanoparticles-Rhodamine B had good stability in cultured Dulbecco's Modified Eagle's-Low Glucose medium and RPMI 1640 medium. The mesenchymal stem cell with multimodal magnetic nanoparticles-Rhodamine B described location of intracellular nanoparticles, which were shown as blue granules co-localized in fluorescent clusters, thus characterizing magnetic and fluorescent properties of multimodal magnetic nanoparticles Rhodamine B. Conclusion: The stability of multimodal magnetic nanoparticles-Rhodamine B found in cultured Dulbecco's Modified Eagle's-Low Glucose medium and RPMI 1640 medium assured intracellular mesenchymal stem cells labeling. This cell labeling did not affect viability of labeled mesenchymal stem cells since they continued to proliferate for five days. (author)
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Energy Technology Data Exchange (ETDEWEB)
Dias, Cristina das Dores. E-mail: crisddias@yahoo.com.br
2003-07-01
This paper reports an experiment for evaluation of the possible genotoxic effects of food prepared in a microwave oven, through the mutation test and somatic recombination, in wings of Drosophila melanogaster. Two crossing have been performed: a standard cross-ST and a high bioactivation cross - HB resulting in marked trans -heterozygote descendents (MH) and balanced heterozygotes (BH). The 72 hours larvas were fed with water and milk boiled both in the microwave oven and in the traditional way. The MH individual wings were analyzed, where the spots can be induced either by mutation or mitotic recombination. The experiment presented negative results related to the genotoxic effects of the water and milk boiled using the microwave oven, in MH descendents of both crossing. Therefore, under these experimental conditions, genotoxic activity were not presented by milk and water boiled in the microwave oven. However, an extensive study using different techniques is necessary to investigate the action of the food prepared in the microwave oven on the genetic material.
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Energy Technology Data Exchange (ETDEWEB)
Garcia, Rafael Henrique Lazzari
2007-07-01
The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher energetic thermal treatments to attain high densities. In relation to the sintered products, it was confirmed the excellent homogeneity and crystallinity of microstructure provided by the chosen route, the restriction of grain growth by alumina addition, raise of hardness and fracture toughness, and higher ionic conductivity, even tough a lower bulk conductivity. These results indicate that the addition of 5 wt % alumina in CSZ matrix allows the application of this material as solid oxide fuel cell electrolytes, due to its better fracture toughness and ionic conductivity, compared to yttria-stabilized cubic zirconia ceramics. (author)
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Energy Technology Data Exchange (ETDEWEB)
Martins, Flaviano dos Santos; Vianna, Cristina Roscoe [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia]|[Minas Gerais Univ, Belo Horizonte, MG (Brazil). Dept. de Microbiologia; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia
2002-07-01
Lyophilized cells of yeast Saccharomyces boulardii were submit to the gamma irradiation ({sup 60} Cobalt). It was noted that the yeast cells surviving to gamma irradiation had more trehalose than control cells. The incubation of cells with H{sub 2}0{sub 2} induces the synthesis of trehalose but the exposition to CdCl{sub 2} induces the accumulation of trehalose only in low concentrations. Apparently there is a positive correlation between of trehalose level and gamma irradiation resistance of S. boulardii cells. It was not observed any correlation with the level of trehalose determined and the oxidative stress tested. (author)
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Energy Technology Data Exchange (ETDEWEB)
Rodrigues, E.R.T.; Nascimento, R.M.; Miranda, A.C. de; Lima, A.M. de, E-mail: erickssonrtr@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Macedo, D.A. [Universidade Federal da Paraiba (UFPB), PB (brazil)
2016-07-01
Fuel cells are devices that convert chemical energy into electricity via redox reactions. In this work, the lanthanum cobaltite doped with strontium and iron (La{sub 0,6}Sr{sub 0,4}Co{sub 0,2}Fe{sub 0,8}O{sub 3} - LSCF) a traditional cathodes material of the fuel cell was mixed with an electrolyte material (composite) to the base ceria doped with gadolinia and a eutectic mixture of lithium carbonates and sodium (CGO-NLC). The powders of LSCF and CGO-NLC were obtained by the citrate method and mixed to obtain a composite cathode. Samples obtained by uniaxial pressure between 5 and 10 MPa were sintered at 1100°C and investigated by X-ray diffraction, scanning electron microscopy and micro hardness test. A symmetric cell cathode / electrolyte / cathode, obtained by co-pressing and co-sintering was investigated by electron microscopy. The results indicated that the composite is chemically stable up to the sintering temperature used. The hardness ranged between 51 and 227 HV. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silva, A.C.; Julio-Junior, O.; Mello-Castanho, S.R.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2010-07-01
Nanostructured catalysts have been developed for ethanol directly use in fuel cells, which due to the economic advantages that should have widespread use in the near future. The catalysts for these devices using nano-structured metal are based, where the toxic nature and environmental risks presented by these metals are largely enhanced by nano-dispersion. Thus, the production of nano-catalysts are potentially generating highly hazardous waste for public health and the environment. This study presents the treatment and inertization of ruthenium (Ru) nanoparticles waste containing by the vitrification technique and consequent attainment of silicate glasses for potential commercial use. Compositions were prepared containing up to about 20 wt % of nano-waste by changing the basic composition of glass soda-lime-borosilicate. After the fusion, at a temperature of 1100 deg C, the glasses were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Infra-red in the Fourier transform (FT-IR) techniques. The chemical stability was evaluated by hydrolytic attack test. The glass containing 20 wt % of nano-residue showed a high chemical stability, similar to a usual soda-lime glass. (author)
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Energy Technology Data Exchange (ETDEWEB)
Guillen, C; Herrero, J; Galiano, F
1990-07-01
Optical an structural properties of electrodeposited copper indium diselenide, CulnSe2, thin films were studied for its application in photovoltaic devices. X-ray diffraction patterns showed that thin films were grown in chalcopyrite phase after suitable treatments. Values of Eg for the CulnSe2 thin films showed a dependence on the deposition potential as determined by optical measurements. (Author) 47 refs.
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Energy Technology Data Exchange (ETDEWEB)
Cruces, M P; Morales R, P [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)
1997-07-01
The mitotic recombination can happen spontaneously and its frequency is very low, however the recombination rate of a cell can be increased by the exposure to agents which cause damage to DNA. This type of agents are knew commonly as recombinogens. The ionizing radiation and a numerous chemical agents can be mentioned (Vogel, 1992). The objective of this work is to determine if the mutation/recombination rate induced by gamma rays varies with the development stage. In order to realize this investigation it was used the mutation and somatic recombination test of Drosophila wing (Graf and col. 1984). The mwh/ mwh and flr{sup 3}/TM3, Ser stocks were used. (Author)
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GPU-Accelerated Optical Coherence Tomography Signal Processing and Visualization
Darbrazi, Seyed Hamid Hosseiny
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Oliveira, Marta Madalena Marques de
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Viscoelastic nanocapsules under flow in microdevices
Cordeiro, Ana Lucinda Teixeira
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Clinopyroxene based glasses and glass-ceramics for functional applications
Goel, Ashutosh
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Rodrigues, Arlete da Silva
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Single Point Incremental Forming and Multi-Stage Incremental Forming on Aluminium Alloy 1050
Suriyaprakan, Premika
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Albumin and fibronectin adsorption and osteoblast adhesion on titanium oxides
Freitas, Susana Maria Ribeiro e. Sousa Mendes de
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Stellar activity in high-precision photometric and spectroscopic transit observations
Oshagh, Mahmoudreza
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Laranjeira, Marta de Sousa
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Impact evaluation of the large scale integration of electric vehicles in the security of supply
Bremermann, Leonardo Elizeire
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Starch and polyethylene based bone-analogue composite biomaterials
Reis, Rui Luis Goncalves dos
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Magnetism at the nanoscale: Nanoparticles, nanowires, nanotubes and their ordered arrays
Proenca, Mariana Jesus Paiva
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Birefringence and Bragg grating control in femtosecond laser written optical circuits
Fernandes, Luis A.
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Improving the characteristics of foundry alloys AlSiCuMg during manufacturing
Fragoso, Bruno Filipe Marques
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Seismic assessment of reinforced concrete frame structures with a new flexibility based element
Arede, Antonio Jose Coelho Dias
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Couto, Diana Manuel Mocho de Bastos
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Ética de la investigación. Las buenas prácticas
Directory of Open Access Journals (Sweden)
López de la Vieja, M.ª Teresa
2008-04-01
Full Text Available The Act 14/2007 regulates biomedical research, including research with stem cells and cloning for therapeutic purposes. The Spanish legislation about those controversial topics could also exemplify the changing perspective about ethical codes and ethical committees, because now they are not only centered on rights, and guarantees for the subjects involved in experimentation, but on good practice. Research Ethics has usually been related to norms, and especially to respect for human rights in the biomedical field. From the Nurmberg Code, the Helsinki Declaration, the Oviedo Convention to the Addition Protocol on biomedical research, the perspective of rights prevailed over a wider perspective, which now aims to promote the researchers’ commitment and their responsibilities to health and welfare; the welfare of every subject, humans, and non-humans, and in every context, including the developing countries. The UNESCO Declaration could expand this perspective, including social justice issues in the agenda of research Ethics, usually centered on autonomy, as basic principle, and on the human rights approach. The article would analyze the good practice approach, with guidelines expanding the agenda of research Ethics in order to promote a better governance of scientific practice.La Ley 14/2007 regula la investigación biomédica, incluida la investigación con células troncales y la clonación con fines terapéuticos. La legislación española sobre estos temas tan controvertidos puede ejemplificar también ciertos cambios en el enfoque sobre códigos éticos y comités de Ética; ahora éstos no sólo se centran en los derechos y las garantías para los sujetos participantes en la experimentación, sino también en las buenas prácticas. La Ética de la investigación ha estado casi siempre asociada con las normas y, en especial, con el respeto por los derechos humanos en el ámbito de la Biomedicina. Desde el Código de Nürnberg, la Declaraci
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Energy Technology Data Exchange (ETDEWEB)
Rodriguez C, J. [Facultad de Medicina, UAEM, 50000 Toluca, Estado de Mexico (Mexico); Ramirez I, M.T. [INCMNSZ, Vasco de Quiroga Num. 15, Tlalpan, 14000 Mexico D.F. (Mexico); Ferro F, G.; Pedraza L, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)
2005-07-01
The radiation toxic effects have been used in therapy however much 50 years. The absorbed radiation dose can be determined at cellular level using cancerous cell cultures. If the deposited In vitro radiation dose coming from similar activities of several therapeutic radiopharmaceuticals it can compare it will be possible to choose the therapeutic radiopharmaceutical that it offers better dosimetric characteristics for the patient. The objective of this original investigation was to determine the union percentage of the octreotide {sup 99m}Tc-HYNlC-TOC to the somatostatin receivers in cells of cancer pancreas as well as the internalization, externalization and cellular viability. It was used the octapeptide, (octreotide, TOC) labelled with {sup 99m}Tc by means of the HYNIC chelating agent (6-hydrazine pyridine-3-carboxylic acid) and 3 cellular lines of murine pancreas cancer (AR42J), of cancer of human pancreas (CAPAN) and of one negative cellular line for somatostatin receivers (WRL-68). The {sup 99m}Tc-HYNIC-TOC was compared against two negative proofs for somatostatin receivers: the peptide {sup 99m}Tc-UBI and the {sup 99m}TcO{sub 4}. The cellular lines were conserved in the synthetic media Dulbecco-Eagle. After 2, 4 and 24 h of exhibition to the radiation, the cells are picked up and its are determined the viability by count in a Neubauer camera using tripan blue. In the same times it was calculated the union percentage of the radiopharmaceutical to the cells and the internalization (union to the cytoplasm) and the externalization (union to membrane receivers). With those figures it was calculated the absorbed radiation dose at cellular level. Results: At 4 hours the union percentage of the {sup 99m}Tc-HYNlC-TOC to the AR42-J cells was 6.83 times greater than for the WRL-68 control cells of human papilloma, (without receivers of the somatostatin) and for the CAPAN them 4 times greater than for the same cells used as negative control, for the case of the {sup 99m}Tc-UBI and the {sup 99m}TcO{sub 4} one doesn't observe a significant difference and the percentage of viability of the AR42-J cells due by the {sup 99m}Tc-HYNlC-TOC it was 20% smaller in comparison with {sup 99m}Tc-UBI and {sup 99m}TcO{sub 4}. The internalization percentage of the AR42-J cells was of 43.28 {+-}1.62 due to the somatostatin receivers that its enter together with the radiopharmaceutical at the interior of the cell and 56.72 {+-}3.25 are together to the cellular membrane. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Rodriguez C, J [Facultad de Medicina, UAEM, 50000 Toluca, Estado de Mexico (Mexico); Ramirez I, M T [INCMNSZ, Vasco de Quiroga Num. 15, Tlalpan, 14000 Mexico D.F. (Mexico); Ferro F, G; Pedraza L, M [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)
2005-07-01
The radiation toxic effects have been used in therapy however much 50 years. The absorbed radiation dose can be determined at cellular level using cancerous cell cultures. If the deposited In vitro radiation dose coming from similar activities of several therapeutic radiopharmaceuticals it can compare it will be possible to choose the therapeutic radiopharmaceutical that it offers better dosimetric characteristics for the patient. The objective of this original investigation was to determine the union percentage of the octreotide {sup 99m}Tc-HYNlC-TOC to the somatostatin receivers in cells of cancer pancreas as well as the internalization, externalization and cellular viability. It was used the octapeptide, (octreotide, TOC) labelled with {sup 99m}Tc by means of the HYNIC chelating agent (6-hydrazine pyridine-3-carboxylic acid) and 3 cellular lines of murine pancreas cancer (AR42J), of cancer of human pancreas (CAPAN) and of one negative cellular line for somatostatin receivers (WRL-68). The {sup 99m}Tc-HYNIC-TOC was compared against two negative proofs for somatostatin receivers: the peptide {sup 99m}Tc-UBI and the {sup 99m}TcO{sub 4}. The cellular lines were conserved in the synthetic media Dulbecco-Eagle. After 2, 4 and 24 h of exhibition to the radiation, the cells are picked up and its are determined the viability by count in a Neubauer camera using tripan blue. In the same times it was calculated the union percentage of the radiopharmaceutical to the cells and the internalization (union to the cytoplasm) and the externalization (union to membrane receivers). With those figures it was calculated the absorbed radiation dose at cellular level. Results: At 4 hours the union percentage of the {sup 99m}Tc-HYNlC-TOC to the AR42-J cells was 6.83 times greater than for the WRL-68 control cells of human papilloma, (without receivers of the somatostatin) and for the CAPAN them 4 times greater than for the same cells used as negative control, for the case of the {sup 99m}Tc-UBI and the {sup 99m}TcO{sub 4} one doesn't observe a significant difference and the percentage of viability of the AR42-J cells due by the {sup 99m}Tc-HYNlC-TOC it was 20% smaller in comparison with {sup 99m}Tc-UBI and {sup 99m}TcO{sub 4}. The internalization percentage of the AR42-J cells was of 43.28 {+-}1.62 due to the somatostatin receivers that its enter together with the radiopharmaceutical at the interior of the cell and 56.72 {+-}3.25 are together to the cellular membrane. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Andrade, Alexandre Bodart de
2008-07-01
The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm{sup 2} active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm{sup -2} at 600 mV. A scaling up study for 144 cm{sup 2} of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool 'Comsol Multiphysics'. For the design of the bipolar plates of the cell the 'Auto CAD' was used. The 144 cm{sup 2} MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW). (author)
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Energy Technology Data Exchange (ETDEWEB)
Brum, F.J.B.; Laux, F.N.; Haack, M.S.; Forte, M.M.C. [Universidade Federal do Rio Grande do Sul. Escola de Engenharia, Porto Alegre, RS (Brazil)
2010-07-01
Monomers with vinyl bond can be polymerized via a cationic mechanism using acid catalysts. This study aimed to obtain homo and copolymers of styrene and indene via cationic mechanism and the functionalization of sulfonic groups to the production of membranes for fuel cells. Polymers and poly electrolytes were characterized by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC/SEC). The degree of sulfonation of the polymers was determined by titration and evaluated for these films to the degree of swelling in water, ion exchange capacity and analysis of electrochemical impedance spectroscopy. Membranes prepared with polyindene and PVA were tested in an apparatus of the fuel cell. (author)
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Energy Technology Data Exchange (ETDEWEB)
Carmo, Marcelo do
2008-12-18
The fuel cell technology associated with the growing exigency of low environmental impact energy became prosperous in the world energy scenery. The fuel cell is basically a device that converts directly the chemical energy of a fuel into electrical and thermal energy with a continuous operation by the constant feed of a fuel. Especially, the carbon black Vulcan XC72 is usually employed as an electro catalyst support, and some factors as an accessible and high surface area in order to get maximum particles dispersion, pore size, adequate pore distribution and the presence of functional groups in the carbon black surface are considered fundamental characteristics for an innovative materials development. However, the Vulcan XC72 still reveals insufficient conditions for these purposes. This study consists in the preparation and in the physical chemical characterization of functionalized carbon black by hydrogen peroxide and by polymeric chains with proton conduction properties, and its posterior utilization as electro catalyst support for PEMFC and DMFC application. After the carbon functionalization, an improvement in the carbon black dispersion in water media was observed, a beneficial effect for electro catalyst preparation. It was also observed, that the functional groups and the polymeric chains worked as stabilizers in the particle growing, producing much more homogeneous electrocatalysts, exhibiting smaller average particle size. Especially, in the case of polymeric chains functionalization, a decrease in the ohmic drop was observed for this system, attributed to an improvement in the proton transference. (author)
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Energy Technology Data Exchange (ETDEWEB)
Andrade, Alexandre Bodart de
2008-07-01
The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm{sup 2} active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm{sup -2} at 600 mV. A scaling up study for 144 cm{sup 2} of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool 'Comsol Multiphysics'. For the design of the bipolar plates of the cell the 'Auto CAD' was used. The 144 cm{sup 2} MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW). (author)
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Energy Technology Data Exchange (ETDEWEB)
Fukurozaki, Sandra Harumi
2006-07-01
The energy is the fuel of growth and an essential requirement for the socioeconomic development. However, the current production model is based on fossil fuels, considered as threat to man and nature. As for, the relating to the human activities and their effects on the environment, they are handled by the implementation of a more rigid model of environmental control and the mobilization of the society in favor of technologies with less energy impact. In view of this scenario, the Proton Exchange Membrane Fuel Cell - PEMFC has been recognized as a key for the vital need of a clean and efficient energy. Considering the conventional power generation system, their advantages during usage configure its application as an ideal option for several utilities, especially in the mobile sector. Even though, the focus on several environmental evaluations in energy systems is referred back to the initial stage of it use, the employment relating to production of the system and to final destination should be considered, since these also present impacts. In the case of PEMFC, their previous and subsequent phases of use are issues related to the platinum catalysts, which indicates an environmental importance that cannot be overlooked. In this sense, the Life Cycle Assessment has been used to understand and to question the risks and opportunities that are associated to certain product, starting from a systemic concept of their relationships with the environment. It is precisely in this context that the present research intends to present its major contribution, starting from an exploratory study towards the its objectives to provide an environmental analysis of such technology linked to post stage of powder-use of the membrane electrode assembly - MEA, concerning the platinum catalysts, on the subject of Life Cycle Assessment - LCA. To attain such aim, the relationships between energy, environment and development are presented and discussed, as well as, the Fuel Cell technology and the current studies on LCA of PEMFC. Several questions raised up on this issues have contributed in the development of a method of recuperating the PEMFC catalysts and, particularly, for its subsequent environmental evaluation. Among significant results are the importance of LCA, out lined as useful tool for perceiving the weight of environmental matters concerning the platinum and its subsidy strategies relating to the development, consolidation and to the innovation of PEMFC. (author)
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Energy Technology Data Exchange (ETDEWEB)
Cruces, M.P.; Pimentel, A.E.; Moreno, A.; Moreno, R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)
2003-07-01
The obtained results using somatic cells, they have evidenced that the chlorophyllin (CHLN) it can act inhibiting or increasing the damage caused by different mutagens. The objective of this investigation is to evaluate the effect of the CHLN on the damage induced by gamma radiation in germinal cells of Drosophila. Two tests were used, the lost of the X chromosome and the conventional test of lethal recessive bound to the sex (LRLS); both with a system of litters. The obtained results in both essays, indicated that the CHLN doesn't reduce the damage induced by the gamma radiation in none of the cellular monitored states. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Cruces, M P; Pimentel, A E; Moreno, A; Moreno, R [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)
2003-07-01
The obtained results using somatic cells, they have evidenced that the chlorophyllin (CHLN) it can act inhibiting or increasing the damage caused by different mutagens. The objective of this investigation is to evaluate the effect of the CHLN on the damage induced by gamma radiation in germinal cells of Drosophila. Two tests were used, the lost of the X chromosome and the conventional test of lethal recessive bound to the sex (LRLS); both with a system of litters. The obtained results in both essays, indicated that the CHLN doesn't reduce the damage induced by the gamma radiation in none of the cellular monitored states. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues; Silva, Cristiane Abrantes da; Soares, Guilherme Fleury Wanderley; Lopes, Francisco da Costa; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: furtado@cepel.br; Codeceira Neto, Alcides [Companhia HidroEletrica do Sao Francisco (CHESF), Recife, PE (Brazil)
2008-07-01
Power systems based on fuel cells have been considered for residential and commercial applications in energy Distributed Generation (DG) market as these systems can minimize their acquisition, installation and operation high costs. In this work we present an experimental analysis of a power generation system formed by a 5 kW proton exchange membrane fuel cell unit and a natural gas reformer (fuel processor) for hydrogen production, of the CEPEL's Fuel Cell Laboratory. It was determined the electrical performance of the cogeneration system in function of the design and operational power plant parameters. Additionally, it was verified the influence of the activation conditions of the fuel cell electrocatalytic system on the system performance. It also appeared that the use of hydrogen produced from the natural gas catalytic reforming provided the system operation in excellent electrothermal stability conditions resulting in increase of the energy conversion efficiency and of the economicity of the cogeneration power plant. The maximum electrical efficiency achieved was around 38% and in all power range unit operated with average potential per single fuel cell higher than 0.60 V. (author)
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Energy Technology Data Exchange (ETDEWEB)
Pires, Filipe Oliveira; Domingues, Rosana Z.; Brant, Marcia C.; Silva, Charles L.; Matencio, Tulio [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica]. E-mail: filipequiufmg@ufmg.br
2008-07-01
Performance of a SOFC may be evaluated by using the AC-Impedance and measuring power (P V x I). The objective of this study was to compare the performance of a fuel cell with LSM as a cathode and another one containing an additional functional composite film LSM/YSZ between the LSM and YSZ. Also it was studied variation in second cell resistance and power according to the temperature, hydrogen flux and operation time. For both cells platinum was used as anode. At 800 deg C was observed, in open current circuit, when the composite layer was introduced a decrease in resistance and high power. These results show an improvement of SOFC cathode performance with the introduction of composite LSM/YSZ layer. The maximum performance of the cell was achieved with 100 mL/min hydrogen flow at 800 deg C. The experiments also showed a performance improvement at 850 deg C. The cell behavior was stable during 318 hours of test. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F., E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Pesquisa em Corrosao; Radtke, C. [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica
2010-07-01
Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)
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Energy Technology Data Exchange (ETDEWEB)
Chiba, R.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC - Insumos e Componentes
2008-07-01
The ceramic material, strontium-doped lanthanum manganite (La{sub 0,85}Sr{sub 0,15}MnO{sub 3} - LSM), has been used as cathode in Solid Oxide Fuel Cells (SOFCs). The cathode attainment as component of the SOFCs has been studied for diverse routes of synthesis and thin films forming in Yttria-stabilized zirconia (ZrO{sub 2}/Y{sub 2}O{sub 3} - YSZ) electrolyte. In this work, the LSM was synthesized by the citrate technique and deposited in YSZ substrate using the forming technique wet powder spraying. Rheological studies of suspensions and chemical, physical and microstructural characterizations of LSM powders were made, aiming at the deposition for thin films formation until 50 mum. The half unit cells LSM/YSZ sintered were characterized by scanning electron microscopy, for verification of porosity and adherence. In this sense, this work is a contribution for production of porous cathode using the forming technique wet powder spraying in the SOFCs. (author)
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Energy Technology Data Exchange (ETDEWEB)
Lima, D.B.P.L. de [Instituto Federal do Parana (IFPR), PR (Brazil); Florio, D.Z. de; Bezerra, M.E.O., E-mail: daniela.bianchi@ifpr.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)
2016-07-01
Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)
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Energy Technology Data Exchange (ETDEWEB)
Guillen, C; Martinez, M A; Dona, J M; Herrero, J; Gutierrez, M T [Ciemat.Madrid (Spain)
2000-07-01
Two different objective have been pursued in the present investigation: (1) optimization of the CuInSe{sub 2} preparation parameters from electrodeposited precursors, and (2) evaluation of their photovoltaic behavior by preparing and enhancing Mo/CuInSe{sub 2}/CdS/TCO devices. When Cu-In-Se precursors are directly electrodeposited, the applied potential fit is essential to improve the photovoltaic performance. Suitable absorbers have been also obtained by evaporing an In layer onto electrodeposited Cu-Se precursors. In this case, the substrate temperature during evaporation determines the CuInSe{sub 2} quality. Similar results have been reached by substituting typical Mo-Coated glass substrates by flexible Mo foils. Different TCO tested (ZnO and ITO) have been found equivalent as front electrical contact in the devices. Solar cell performance can be improved by annealing in air at 200 degree centigree. (Author) 46 refs.
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Energy Technology Data Exchange (ETDEWEB)
Oliveira, R.N.; Furtado, J.G. de M.; Soares, C.M.; Serra, E.T. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)], e-mail: rnunes@cepel.br
2006-07-01
This work has for objective to investigate and to characterize the microstructural development of lanthanum chromite-based ceramics (LaCrO{sub 3}) doped with earth alkaline metals, correlating the microstructural parameters (mainly the densification level) and processing parameters with the electrothermal properties reached. Lanthanum chromite-based ceramic systems doped with earth-alkaline metals (Ca, Mg and Sr) had been produced from respective metallic nitrates by solid state reactions process. The phase compositions were evaluated by X-ray diffraction and the densification level by Archimedes method. The microstructural characterization was effected by scanning electron microscopy, energy dispersive X-ray spectroscopy and thermal analysis techniques. Electrical tests were used to evaluate the electrical conductivity of the studied ceramics. The obtained results corroborate the literature comments concerning the difficulty of lanthanum chromite-based ceramics with high densification level and evidence the great influence of the nature of the dopants on the sintering mechanism and the microstructural and electric characteristics of the produced ceramics. The best ones results, in terms of densification and electrical conductivity, had been gotten through multiple doping with calcium and strontium, and in sintering temperature conditions lower that the normally considered to pure or monodoped lanthanum chromite-based ceramics. (author)
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Energy Technology Data Exchange (ETDEWEB)
Santos, Antonio Rodolfo dos
2007-07-01
This work reports results of studies and characterization on membrane electrode assemblies (MEAs) for proton exchange membrane fuel cell (PEMFC). Some cell operation conditions and different processes of MEA production were investigated. The electrochemical impedance spectroscopy technique (EIS) (in situ - 0 to 16 A) was used 'on-line' as a tool for diagnosis, concerning the cell performance. The EIS measurements were carried out with a FC350 Fuel Cell EIS System (GAMRY), coupled to a PC4 potentiostat/galvanostat and connected to the electronic load (TDI) for 'on-line' EIS experiments (100 mHz - 10 kHz, dU = 5 mV). MEAs with 25 cm{sup 2} surface area, using PtM/C 20% (M Ru, Sn or Ni) electrocatalysts were manufactured using the alcohol reduction process (ARP). The catalytic ink was applied directly into the carbon cloth (GDL) and pressed in the Nafion membrane (105). MEAs using Pt/C and Pt Ru/C 20% from E-TEK electrocatalysts were manufactured by comparison. All the cathodes were sprayed with Pt/C 20% from E-TEK. The noble metal concentrations used were set to 0.4 mg Pt.cm{sup -2} at the anode and 0.6 mg Pt.cm{sup -2} at the cathode (E-TEK). Nyquist diagrams of the MEAs with Pt/C and PtRu/C from E-TEK or PtM/C (M = Ru, Sn or Ni) ARP showed essentially the same ohmic resistances for the MEAs. This fact can be explained by suppression of agglomerates during the MEA preparation process or by the homogeneity of the anchored electrocatalysts at the carbon surface. It could also be observed, at low current densities, that there was a significant performance difference between the electrocatalysts from E-TEK and those prepared with the alcohol reduction process. The polarization curves results confirmed that the Pt M/C (M = Ru, Sn or Ni) ARP showed an activity increase for the methanol and ethanol fed cells. The technique of EIE was shown efficient for the evaluation of the method preparation of MEAs and the acting of the cell, the results of EIE showed coherence in the choice of the model the electric circuit for MEAs using hydrogen, methanol and ethanol. This coherence indicates that other resistances no considered in the model are not relevant in the total resistance of MEAs. (author)
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Growth of Pediococcus acidilactici on sugar cane blackstrap molasses
Directory of Open Access Journals (Sweden)
Ernani S. Sant’Anna
1998-09-01
Full Text Available Pediococcus acidilactici (IL01 has grown in MRS (Man, Rogosa and Sharpe broth modified by substitution of glucose by 2.0% (MRS-2, 3.0% (MRS-3, 4.0% (MRS-4 and 5.0% (MRS-5 sugar cane blackstrap molasses. The highest acid production was obtained in MRS-5 broth maintained at a constant pH of 5.0. The highest biomass production was obtained when P. acidilactici was grown in MRS-5 broth at initial pH 6.5, while productivity was higher in MRS-2 broth (28.16%. When the MRS-2 broth was utilized at initial pH 6.5 for a 20-hour fermentation period, the highest growth rate (dx/dt was found in a period of 8 to 16 hours (0.290 g cells/L.h, while the specific growth rate (µ was 0.175 (h-1 for that period, differently from the 0.441 (h-1 obtained for the period comprising the 4th to the 12th hour. The growth in MRS broth was 5.08% (2.95 g/l higher than in MRS-2 broth (2.80 g/l. The data obtained have shown that P. acidilactici has had a significant growth in molasses as the main carbon source, and that it is possible to substitute MRS glucose by this carbon source with the purpose of obtaining a more economical growth medium for the potential large scale productions.Pediococcus acidilactici (IL01 cresceu em caldo MRS (Man, Rogosa and Sharpe modificado por adição de 2,0% (MRS-2, 3,0% (MRS-3, 4,0% (MRS-4 and 5,0% (MRS-5 de melaço de cana de açúcar, em substituição à glicose. A maior produção de ácido ocorreu em caldo MRS-5 com pH constante 5,0. A produção de biomassa foi mais acentuada em caldo MRS-5 com pH inicial de 6,5, embora a produtividade tenha sido maior em caldo MRS-2 (28,16%. Em caldo MRS-2 e em pH inicial de 6,5 durante uma fermentação de 20 horas, a velocidade de crescimento (dx/dt foi maior entre a 8ª e 16ª hora (0,290 g celulas/L.h enquanto a velocidade específica de crescimento µ foi 0,175 (h-1 para este período, diferente de 0,441 (h-1 obtido no período compreendido entre a 4ª e 12ª hora. O crescimento em caldo MRS foi 5
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Alterações hematológicas em bovinos submetidos ao envenenamento crotálico
Directory of Open Access Journals (Sweden)
P. M. Ferreira
2005-03-01
Full Text Available RESUMO: O quadro clÃnico observado ao exame do animal acidentado pela cascavél sul americana (Crotalus durissus terrificus , portadora de veneno contendo quantidades significativas da toxina crotamina, é de difÃcil diferenciação clÃnica com outras doenças. Com o objetivo de se estabelecer alterações hematológicas que auxiliem o diagnóstico desta condição mórbida, cinco fêmeas bovinas mestiças, com idade variando entre dois e três anos, foram inoculadas com veneno crotálico do tipo crotamina positivo, utilizando a dose de 0,03 mg por quilo de pêso vivo, na região glútea, por via intramuscular. Colheu-se amostras de sangue para realizar os exames laboratoriais antes e a cada duas horas após a inoculação, até a morte dos animais. Verificou-se que: o número de hemácias, o volume corpuscular médio ( VCM , a hemoglobina corpuscular média ( HCM , os números de leucócitos totais, de linfócitos, de neutrófilos e de monócitos, tiveram aumentos significativos e que os números de leucócitos totais apresentaram comportamento atÃpico, caracterizado por leucocitoses com valores atingindo até 60.000 celulas/mm,3 a cada seis horas, alternadas por quedas para em torno de 13.000 células/mm3. Pelo exposto, concluiu-se que a observação destas alterações poderá auxiliar o estabelecimento do diagnóstico desta afecção nos bovinos. PALAVRAS CHAVE: Envenenamento crotálico; hemograma; bovinos. SUMMARY: The clinical findings observed at examination of an animal attacked by South American rattle snake (Crotalus durissus terrificus , that has poison containing significative crotamine toxin quantites are difficult to distinguish from other diseases. With the aim of establishing haematological parameters of diagnostic value for this condition diagnosis, five crossbred female cattle, from two to three years old, were inoculated with
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Directory of Open Access Journals (Sweden)
B. Gal-Iglesias
2009-06-01
Full Text Available Introducción. El estudio integrado de la fisiología y la anatomía constituye una asignatura troncal dentro de las titulaciones de ciencias de la salud. La adaptación de la enseñanza de esta materia al estándar de Bolonia supone un reto metodológico dada su complejidad curricular y sus perfiles competenciales específicos. Objetivos. Evaluar experimentalmente una metodología mixta en la enseñanza de la fisiología y anatomía tanto en los resultados del aprendizaje como en la adquisición de competencias de los alumnos, así como desarrollar un baremo de medición del aprendizaje. Sujetos y métodos. Se comparan los resultados del aprendizaje en la diplomatura de podología de la Universidad Europea de Madrid entre un grupo control (metodología clásica: lección magistral y uno experimental (metodología mixta: problemas, casos clínicos, trabajo en grupo y lección magistral. Resultados. Se muestra que con una aproximación mixta los alumnos adquieren habilidades y competencias a lo largo del curso, estabilizándose el aprendizaje lo suficiente y equilibrándose las diferencias individuales, en contraste con el grupo control. Esta homogeneización del aprendizaje se manifiesta como una menor variabilidad de la nota media de los exámenes en el grupo experimental, e indica el soporte que supone el método mixto para el aprendizaje de los alumnos con mayores dificultades. Se detecta una fuerte regresión lineal entre la asistencia a clase y los resultados del aprendizaje, y se confirma la importancia de la supervisión del proceso de aprendizaje por parte del profesor. Conclusión. El método mixto de enseñanza de la fisiología y la anatomía permite a los alumnos adquirir habilidades y competencias a lo largo del curso, equilibrando las diferencias como parte del proceso de aprendizaje.Introduction. The integrated study of Anatomy and Physiology is mandatory in Health Sciences careers. The adaptation of these topics to the Bolonia
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Directory of Open Access Journals (Sweden)
Edwin Causado Rodríguez
2014-01-01
Full Text Available El presente trabajo tiene como finalidad identificar mediante la aplicación del método de precios hedónicos expresado en un modelo econométrico, las variables determinantes del valor de los predios de las áreas de Pozos Colorados, Bello Horizonte y Don Jaca de la ciudad de Santa Marta, incluyendo la variable ambiental en la cuantificación económica de este. Este estudio, es de gran importancia debido a que en Colombia y, sobre todo, en el departamento del Magdalena, concretamente en la ciudad de Santa Marta, no se han realizado estudios de valoración económica con inclusión de la variable ambiental y tampoco de cuantificación de impacto ambiental en el valor de un predio expuesto a una externalidad del sector productivo. A través de la metodología de precios hedónicos, se pretendió evaluar información actualizada de precios de predios para el año 2005; identificando seis variables, de las cuales sólo una resultó no tener ninguna relevancia, ni incidencia sobre el precio de los predios del área de estudio, siendo esta la de estrato. En cuanto a las cinco variables restantes; superficie del terreno (M2, área construida (M2, proximidad al puerto de PRODECO, proximidad a la playa y proximidad a vía de acceso principal y de circulación de tractomulas que transportan carbón (Troncal del Caribe, mostraron tener incidencias sobre el precio del suelo de las área de Pozos Colorados, Bello Horizonte y Don Jaca de la ciudad de Santa Marta D.T.C.H, incluyendo la variable ambiental en el precio de estos predios.Palabras Clave: Precios Hedónicos; Precio del Suelo; Valoración económica; Impacto Ambiental Carbón; Pozos Colorados; Bello Horizonte; Don Jaca. Estimate of a hedonistic model for the Price of properties in the áreas of Pozos Colorados, Bello Horizonte and Don Jaca of the city of Santa Marta D.T.C.H, Colombia.AbstractThe purpose of this article is to identify the determining variables of the price of real estate in the
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Energy Technology Data Exchange (ETDEWEB)
Robalinho, Eric
2009-07-01
This work presents the development of a numerical computer model and methodology to study and design polymeric exchange membrane fuel cell - PEM. For the validation of experimental results, a sequence of routines, appropriate to fit the data obtained in the laboratory, was described. At the computational implementation it was created a new strategy of coupling two 3-dimensional models to satisfy the requirements of the comprehensive model of the fuel cell, including its various geometries and materials, as well as the various physical and chemical processes simulated. To effective assessment of the real cell analogy with numerical model, numerical studies were carried out. Comparisons with values obtained in the literature, characterization of variables through laboratory experiments and estimates from models already tested in the literature were also performed. Regarding the experimental part, a prototype of a fuel cell unit of 144 cm{sup 2} of geometric area was designed, produced and operated at laboratory with the purpose of validating the numerical computer model proposed, with positive results. The results of simulations for the 2D and 3D geometries proposed are presented in the form of polarization curves, highlighting the catalytic layer model based on the geometry of agglomerates. Parametric and sensitivity studies are presented to illustrate the change in performance of the fuel cell studied. The final model is robust and useful as a tool for design and optimization of PEM type fuel cells in a wide range of operating conditions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Robalinho, Eric
2009-07-01
This work presents the development of a numerical computer model and methodology to study and design polymeric exchange membrane fuel cell - PEM. For the validation of experimental results, a sequence of routines, appropriate to fit the data obtained in the laboratory, was described. At the computational implementation it was created a new strategy of coupling two 3-dimensional models to satisfy the requirements of the comprehensive model of the fuel cell, including its various geometries and materials, as well as the various physical and chemical processes simulated. To effective assessment of the real cell analogy with numerical model, numerical studies were carried out. Comparisons with values obtained in the literature, characterization of variables through laboratory experiments and estimates from models already tested in the literature were also performed. Regarding the experimental part, a prototype of a fuel cell unit of 144 cm of geometric area was designed, produced and operated at laboratory with the purpose of validating the numerical computer model proposed, with positive results. The results of simulations for the 2D and 3D geometries proposed are presented in the form of polarization curves, highlighting the catalytic layer model based on the geometry of agglomerates. Parametric and sensitivity studies are presented to illustrate the change in performance of the fuel cell studied. The final model is robust and useful as a tool for design and optimization of PEM type fuel cells in a wide range of operating conditions. (author)
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Energy Technology Data Exchange (ETDEWEB)
Moreno M, A
2005-07-01
The chlorophyllin (CHLN) is a derived of the chlorophyll in the one which the atom of Mg is replaced by Cu. It has been broadly used as preservative in those foods, and in the treatment of geriatric patients. The results using different test systems have demonstrated that the CHLN reduces the DNA damage caused by different physical agents or chemical of direct action or insinuation. Another of the properties of the CHLN is it anti carcinogenic action, because it has been that inhibits the carcinogen activity of B1 (AFB1) aflatoxin and it diminishes the incidence of tumors caused for 2-amine-3-methylimidazo [4- 5f] quinoline (IQ) and it inhibits the development of colon cancer during the post-initiation phase. Recently the reports of the activity promoter of the CHLN have been increased on the genetic damage. This effect observed in Salmonella and later on in Drosophila melanogaster using, physical and chemical agents. Presently study determines the action of the CHLN before the genetic effect induced in germinal cells of Drosophila melanogaster by means of the test of the lost one of the X chromosome in ring using two protocols; the first one consisted on pretreatment with CHLN to the male ones and later on to irradiate them and in the second protocol the pretreatment with CHLN administers to the females, in both protocols its were used a litter systems. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de, E-mail: faili.cintia@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia. Departamento de Materiais; Cava, S.S. [Universidade Federal de Pelotas, RS (Brazil)
2016-07-01
The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)
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Energy Technology Data Exchange (ETDEWEB)
Silva, Sergio Batista da
2010-11-15
The lack of electricity in isolated communities in the Brazilian Amazon has become one of the greatest barrier for the development of the region. Currently, the main technologies that provide electricity to these communities are diesel generators, batteries and dry cells. These non-renewable energy sources may pose serious problems to the environment and human health and have high maintenance and operational costs. Therefore, the search for renewable energy sources, such as water and sunlight, which are highly abundant in the region, has become a great challenge. This thesis presents the studies on application of solar photovoltaic (PV) and fuel cell (FC) technologies to supply electric power in an uninterrupted manner. Outlined are the technical and cost issues of a pilot project set up in an environmentally protected area, next to Bananal island, located in the Southwestern region of the state of Tocantins. The pilot project relies on PV solar power as the primary source of energy for the production of electricity. The surplus energy is stored in the form of hydrogen produced by electrolysis of the water supplied locally, which is reconverted into electric power by fuel cells during periods when there is little or no sunlight. In this context, the aim of the study was to propose a sizing of a hybrid distributed generation system (HDGS), comprised of a PV system, FC and batteries, that optimizes implementation and operational costs, as a potential source of energy for isolated communities in the Amazon. The work was carried out with the help of simulation software HOMER (Hybrid Optimization Model for Electric Renewable) developed by National Renewable Energy Laboratory (NREL). Simulations and a comparative study were carried out of the technologies and potential configurations that meet the needs of these isolated communities. The results showed an optimal solution of HGDS PV-FC batteries with a reduction in the initial cost of the project in about 60% compared to the sizing system only. The HOMER simulated results also indicated that more than 50% of the costs of the PV-FC-battery HDGS regarded the PV system. (author)
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Energy Technology Data Exchange (ETDEWEB)
Grande Azanedo, M.T.
1989-02-01
The proliferative activity of CFU-S, low in normal steady state, increases after treatment with different aggressors, i.e., radiation. This stimulation has been attributed in part to a local regulation system of stem cell proliferation, and at least in part to a humoral regulatory system. In the present work it has been investigated the role that circulating activities have in the CFU-S stimulation, by means of in vitro and in vivo incubation assays with diffusion chambers. The results show that bone marrow of mice irradiated with 5 Gy produces in vitro diffusible activities capable of stimulating the CFU-S proliferation. As well with this same dose circulating activities are also produced in vivo. In addition we have observed that these activities are only released during the periods of active hematopoietic regeneration that follow irradiation with moderate doses (1.5 and 5 Gy). In another set of experiments we saw that the stimulating activities are also detected in serum of mice irradiated with 5 Gy. These serum activities modify the proliferative state of very primitive precursors (12 d CFU-S). When the serum activities are added to long term bone marrow cultures the CFU-S are also stimulated to proliferate. Finally, we observed that the radiation-induced serum activities stimulate the proliferation of bone marrow CFU-S when injected into normal mice, suggesting that such activities are involved in the regulation of CFU-S proliferation.
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Energy Technology Data Exchange (ETDEWEB)
Policastro, Lucia L; Duran, Hebe; Molinari, Beatriz L [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia; Schuff, Juan A; Kreiner, Andres J; Burlon, Alejandro A; Debray, Mario E; Kesque, Jose M; Ozafran, Mabel J; Vazquez, Monica E [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Fisica; Davidson, Jorge; Davidson, Miguel [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina); Somacal, Hector R; Valda, Alejandro A [Universidad Nacional de General San Martin , Villa Ballester (Argentina). Escuela de Ciencia y Tecnologia
2003-07-01
Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with {gamma} rays and proton beams. Irradiations were performed with a {sup 137}Cs {gamma} source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the {alpha} parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.69{+-}0.08 keV/{mu}m). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with {gamma} rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with {gamma} rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with {gamma} rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)
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Energy Technology Data Exchange (ETDEWEB)
Garavaglia, Ricardo N; Farias, Silvia S; Rodriguez, Ruben E; Servant, Roberto E; Liberman, Sara; Pisarev, Mario A; Batistoni, Daniel A [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Quimica
1999-07-01
This paper describes the development and optimization of methodology for total boron concentration in cell cultures coming from fixation and accumulation of this element by normal and malignant cells. On account of sample mass and low volume resulting from dilution, generally about 1 mL, a procedure for automatic injection of micro volumes was designed, developed and optimized. Iron interference was carefully studied. Linear calibration curves were obtained for 50 to 2500 ng B/mL range. Determination limits were 10 and 20 ng B/mL for B 249.772 nm and 249.677 nm, respectively. Repeatability, expressed as relative standard deviation was better than 5% for a 100 ng B/mL. Recovery of analyte added to real samples ranged between 95 and 103%. The method was applied to studies on F-98 cells (rat glioma) and normal glia in BNCT project frame. (author)
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Energy Technology Data Exchange (ETDEWEB)
Santos, Antonio Rodolfo dos
2007-07-01
This work reports results of studies and characterization on membrane electrode assemblies (MEAs) for proton exchange membrane fuel cell (PEMFC). Some cell operation conditions and different processes of MEA production were investigated. The electrochemical impedance spectroscopy technique (EIS) (in situ - 0 to 16 A) was used 'on-line' as a tool for diagnosis, concerning the cell performance. The EIS measurements were carried out with a FC350 Fuel Cell EIS System (GAMRY), coupled to a PC4 potentiostat/galvanostat and connected to the electronic load (TDI) for 'on-line' EIS experiments (100 mHz - 10 kHz, dU = 5 mV). MEAs with 25 cm{sup 2} surface area, using PtM/C 20% (M Ru, Sn or Ni) electrocatalysts were manufactured using the alcohol reduction process (ARP). The catalytic ink was applied directly into the carbon cloth (GDL) and pressed in the Nafion membrane (105). MEAs using Pt/C and Pt Ru/C 20% from E-TEK electrocatalysts were manufactured by comparison. All the cathodes were sprayed with Pt/C 20% from E-TEK. The noble metal concentrations used were set to 0.4 mg Pt.cm{sup -2} at the anode and 0.6 mg Pt.cm{sup -2} at the cathode (E-TEK). Nyquist diagrams of the MEAs with Pt/C and PtRu/C from E-TEK or PtM/C (M = Ru, Sn or Ni) ARP showed essentially the same ohmic resistances for the MEAs. This fact can be explained by suppression of agglomerates during the MEA preparation process or by the homogeneity of the anchored electrocatalysts at the carbon surface. It could also be observed, at low current densities, that there was a significant performance difference between the electrocatalysts from E-TEK and those prepared with the alcohol reduction process. The polarization curves results confirmed that the Pt M/C (M = Ru, Sn or Ni) ARP showed an activity increase for the methanol and ethanol fed cells. The technique of EIE was shown efficient for the evaluation of the method preparation of MEAs and the acting of the cell, the results of EIE showed coherence in the choice of the model the electric circuit for MEAs using hydrogen, methanol and ethanol. This coherence indicates that other resistances no considered in the model are not relevant in the total resistance of MEAs. (author)
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Energy Technology Data Exchange (ETDEWEB)
Akca, Ozlet; Unak, Perihan; Medine, E. Ylker [Ege University (Turkey). Institute of Nuclear Sciences. Department of Nuclear Applications; Sakarya, Serhan [Adnan Menderes University (Turkey). ADUBILTEM Science and Technology Research and Development Center; Ozdemir, Caglar; Timur, Suna [Ege University (Turkey). Science Faculty. Department of Nuclear Applications
2011-07-01
Silane modified magnetic nanoparticles were prepared after capped with silica generated from the hydrolyzation of tetraethyl orthosilicate (TEOS). Amino silane (SG-Si900) was added to this solution for surface modification of silica coated magnetic particles. Finally, D-penicillamine (D-PA)-antimetadherin (anti-MTDH) was covalently linked to the amine group using glutaraldehyde as cross-linker. Magnetic nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and atomic force microscopy (AFM). AFM results showed that particles are nearly monodisperse, and the average size of particles was 40 to 50 nm. An amino acid derivative D-PA was conjugated anti-MTDH, which results the increase of uptaking potential of a conjugated agent, labelled fluorescein isothiocyanate (FITC) and then conjugated to the magnetic nanoparticles. In vitro evaluation of the conjugated D-PA-anti-MTDH-FITC to magnetic nanoparticle was studied on MCF-7 breast cancer cell lines. Fluorescence microscopy images of cells after incubation of the sample were obtained to monitor the interaction of the sample with the cancerous cells. Incorporation on cells of FITC labeled and magnetic nanoparticles conjugated D-PA-anti-MTDH was found higher than FITC labeled D-PA-anti-MTDH. The results show that magnetic properties and application of magnetic field increased incorporation rates. The obtained D-PA-anti-MTDH-magnetic nanoparticles-FITC complex has been used for in vitro imaging of breast cancer cells. FITC labeled and magnetic nanoparticles conjugated D-PA-anti-MTDH may be useful as a new class of scintigraphic agents. Results of this study are sufficiently encouraging to bring about further evaluation of this and related compounds for ultraviolet magnetic resonance (UV-MR) dual imaging. (author)
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Energy Technology Data Exchange (ETDEWEB)
Braga, Jose Mauro Fernandes [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Escola de Engenharia]. E-mail: jmfbraga@oi.com.br; Seidl, Peter [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Pirro e Longo, Waldimir [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Nwcleo de Estudos Estrategicos (NEST)
2008-07-01
This work aims to demonstrate the economic viability of the application of industrial hydrogen in fuel cell systems by analyzing the advantages and disadvantages of this investment in hydrochloric acid/ sodium hydroxide plants. Using the Present Liquid Value and the Real Options Theory an economic evaluation will be made of the integration of fuel cell system in these plants, based on investment cost, volatility, among other parameters. (author)
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Energy Technology Data Exchange (ETDEWEB)
Mallmann, Ana Paula
2011-01-15
Photovoltaic solar energy is the direct conversion of solar energy into electricity and it has low impact to the environment during electric energy production. The main device of this technology is the solar cell and silicon is the substrate most used. The solar cells are electrically connected and encapsulated in order to form the photovoltaic module. The aims of this thesis are to optimize, develop and to analyse n{sup +}np{sup +} solar cells processed in n type Si-PV-FZ and with aluminum rear emitter formed in belt furnace. The optimization of solar cells by simulation is an important step before the device development. The software PC-1D and another program developed using Visual Basic language were used. Considering a metal grid formed by evaporation technique in vacuum ambient an efficiency of 16.8 % may be achieved. With screen printed grid, 15.8 % efficient solar cells were obtained. From the simulation results it was found that the screen printing metallization may become more viable than evaporation technique because there is low difference in the efficiency and the screen printing is a simpler technique. The experimental optimization of silicon wafers texture process resulted in reflectance of 12 %. This value is typical for monocrystalline silicon with textured surface. Experimental optimization of phosphorus front surface field shows a sheet resistance of (36 {+-} 4) {omega}/ for this region. This region was formed in a thermal step in a conventional furnace with POCl{sub 3}. It was found that after the phosphorus diffusion occurred gettering to specific temperature and time. It was verified that the minority carrier lifetime in the final of processing is similar to the initial value. The influence of steps sequence of front silver paste firing and rear diffusion/firing aluminium paste, of surface passivation and the influence of dry air flow during the aluminium paste diffusion/firing, of aluminium paste diffusion/firing temperature and of belt speed under the fabricated devices electric characteristics were analysed. The aluminum rear emitter n{sup +}np{sup +} silicon solar cells resulted in 29 efficiency up to 9,5 %. The best solar cells were processed under 900 deg C to aluminium paste diffusion/firing and belt speed of 140 cm/min. The efficiency is limited by low values of V{sub OC} and FF reached. It was also verified that the local rear emitter formation results in solar cells with higher efficiency than those with homogeneous emitter. (author)
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Energy Technology Data Exchange (ETDEWEB)
Matos, Bruno Ribeiro de
2008-11-06
The fabrication and characterization of Nafion - TiO{sub 2} composites, and the use of such electrolytes in PEM (Proton Exchange Membrane) fuel cell operating at high temperature (130 deg C) were studied. The operation of a PEM fuel cell at such high temperature is considered as an effective way to promote fast electrode reaction kinetics, high diffusional transport, and high tolerance to the carbon monoxide fuel contaminant. The polymer Nafion{sup R} is the most used electrolyte in PEM fuel cells due to its high proton conductivity. However, the proton transport in Nafion is dependent on the water content in the polymeric membrane. The need of absorbed water in the polymer structure limits the operation of the fuel cell to temperatures close to 100 deg C, above which Nafion exhibits a fast decrease of the ionic conductivity. In order to increase the performance of the electrolyte operating at high temperatures, Nafion-TiO{sub 2} composites have been prepared by casting. The addition of titania hygroscopic particles to the polymeric matrix aims at the enhancement of the humidification of the electrolyte at temperatures above 100 deg C. Three types of titania particles with different specific surface area and morphology have been investigated. Nafion-based composites with the addition of titania nanoparticles, in the 2.5-15 wt.% range, with nearly spherical shape and specific surface area up to approx. 115 m{sup 2}g{sup -1} were found to have higher glass transition temperature than the polymer. Such an increase improves the stability of the electrolyte during the fuel cell operation at high temperatures. The addition of titania-derived nanotubes results in a pronounced increase of the performance of PEM fuel cell operating at 130 deg C. In this composite, the high specific surface area and the tubular shape of the inorganic phase are responsible for the measured increase of both the absorption and retention of water of the composite electrolyte. Nonetheless, the polarization curves of fuel cell using the composite electrolytes exhibited an increase of the ohmic polarization associated with the addition of the insulating titania particles. As the chemical structure of Nafion was observed to be insensitive to the addition of the inorganic particles, the high performance of the composite electrolytes is a result of competing effects: the decrease of the electrical conductivity and a higher thermal stability or water absorption/retention capacity. The experimental results suggest that the Nafion-TiO{sub 2} composites are promising electrolytes for PEM fuel cells operating at temperatures above approx. 100 deg C. (author)
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Energy Technology Data Exchange (ETDEWEB)
Cronkite, E. P.; Fliedner, T. M.; Killmann, S. A.; Rubini, J. R. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)
1962-02-15
energia, permite obtener autorradiogramas (ARG) de elevada resolucion. La {sup 3}HTDR es quimicamente estable, marca el acido desoxirribonucleico (ADN) y no experimenta intercambio ulterior. El ADN solo es diluido por nuevo ADN en el momento de producirse las duplicaciones cromosomaticas. Por tanto, la intensidad de la marcacion disminuye a medida que tienen lugar las sucesivas divisiones celulares. Al parecer, el comportamiento de la poblacion marcada es compatible con el modelo Taylor-Woods-Hughes (TWH) de duplicacion cromosomatica. La intuicion sugiere que el ADN adquiere radiotoxicidad cuando se le incorporan elementos radiactivos. Se ha estudiado la toxicidad en relacion con las propiedades del tritio y la influencia de la duplicacion cromosomatica (modelo TWH), y empiricamente en testiculos y linfocitos de mamiferos. Despues de administrar dosis suficientes para poder realizar estudios autorradiograficos en serie, no se han observado radiolesiones ni perturbaciones en la proliferacion celular. Hasta la fecha se han estudiado, tanto en el hombre como en animales, la hematopoyesis normal, leucemias agudas y cronicas, mieloma multiple y determinados tumores solidos. Se ha reunido una serie de datos sobre la fraccion de las celulas marcadas y la velocidad de disminucion de la intensidad de la marcacion. En la memoria se presentan esos datos. Su interpretacion resulta complicada a consecuencia de las restricciones impuestas por la identificacion citologica y de la determinacion de limites morfologicos entre fases sucesivas de la proliferacion celular pasando de la celula originaria a la progenie que no sufre division, asi como de nuestra incapacidad para determinar si una celuia que no este en estado de mitosis o en fase de sintesis de ADN conserva su capacidad para volver a dividirse. En la memoria se examinan los aspectos teorico y practico de estos problemas. Se ha establecido provisionalmente que la velocidad de crecimiento correspondiente a algunos conjuntos
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Energy Technology Data Exchange (ETDEWEB)
Bonifacio, Rafael Nogueira
2013-07-01
PEMFC systems are capable of generating electricity with high efficiency and low or no emissions, but durability and cost issues prevent its large commercialization. In this work MEA with palladium based catalysts were developed, Pd/C, Pt/C and alloys PdPt/C catalysts with different ratios between metals and carbon were synthesized and characterized. A study of the ratio between catalyst and Nafion Ionomer for formation of high performance triple-phase reaction was carried out, a mathematical model to implement this adjustment to catalysts with different relations between metal and support taking into account the volumetric aspects of the catalyst layer was developed and then a study of the catalyst layer thickness was performed. X-ray diffraction, Transmission and Scanning Electron Microscopy, X-ray Energy Dispersive, Gas Pycnometry, Mercury Intrusion Porosimetry, Gas adsorption according to the BET and BJH equations, and Thermo Gravimetric Analysis techniques were used for characterization and particle size, specific surface areas and lattice parameters determinations were also carried out. All catalysts were used on MEAs preparation and evaluated in 5 cm{sup 2} single cell from 25 to 100 °C at 1 atm and the best composition was also evaluated at 3 atm. In the study of metals for reactions, to reduce the platinum applied to the electrodes without performance losses, Pd/C and PdPt/C 1:1 were selected for anodes and cathodes, respectively. The developed MEA structure used 0,25 mgPt.cm{sup -2}, showing power densities up to 550 mW.cm{sup -2} and power of 2.2 kW{sub net} per gram of platinum. The estimated costs showed that there was a reduction of up to 64.5 %, compared to the MEA structures previously known. Depending on the temperature and operating pressure, values from US$ 1,475.30 to prepare MEAs for each installed kilowatt were obtained. Taking into account recent studies, it was concluded that the cost of the developed MEA is compatible with PEMFC stationary application. (author)
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Energy Technology Data Exchange (ETDEWEB)
Morales N, I
2006-07-01
The cupro-sodium chlorophyllin (CCS) it is a soluble porphyrin in water that it includes in its it structures a copper atom instead of the magnesium that has the chlorophyll. Diverse experiments have demonstrated that it possesses a potent activity, reducing or inhibiting, the DNA damage caused by physical and chemical agents of direct action or insinuation. Most of the knowledge about their anti genotoxic activity has been obtained using somatic cells of different organisms, on the other hand it is known very little of their effect in germinal cells. At the moment in the Drosophila laboratory of the ININ it is investigating the protective action of the CCS in germinal cells, with these studies has been observed that its administration to females that were crossed with males irradiated with 20 Gy of gamma radiation, promotes the induction of lethal dominant in the embryonic and post-embryonic states causing a diminution in the viability egg-adult. With the test of lethal recessive bound to the sex one has evidence that it increases the basal frequency of lethal recessive and it doesn't reduce those induced by radiation. In contrast, with the present investigation when the CCS was administered to males that later on were treated with ethyl-nitroso-urea (ENU) caused a reduction of the lethal frequency in all the monitored cellular states, but only it was significant in the post-meiotic cells. On the contrary, when the CCS was administered to the female ones and then they crossed with males treaties with ENU, it was observed a tendency to increase the lethal ones in all the cellular types. With both protocols the CCS caused a diminution of the sterility. The fact that the CCS has antagonistic activities, it deserves special attention to investigate with different protocols and systems, the conditions in that this pigment can work as a true antimutagenic and/or anti carcinogenic before being able to him to propose as a chemopreventor. (Author)
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Directory of Open Access Journals (Sweden)
Muñoz, Emilio
2009-08-01
en el que han intervenido una serie de patologías que han sido diagnosticadas a través de una serie de revisiones críticas emprendidas por el autor dentro del marco de un programa sobre “filosofía de la política científica”. A través del recurso a metáforas médicas y clínicas he podido construir una historia clínica en la que se describen las patologías y sus diagnósticos, asociadas simbólicamente a trastornos mentales y sensoriales. Entre ellos cabe mencionar procesos de amnesia, del que es un ejemplo la disociación entre lenguaje y acción motora (discurso y acción; la deficiente comprensión de conceptos en el trinomio básico I+D+innovación y de las relaciones entre ellos; frecuentes errores de percepción (visión y audición respecto al sentido y uso de los indicadores habituales; el tránsito, dependiente de circunstancias ajenas al propio objeto de la política de ciencia y tecnología, desde la euforia a la depresión (trastorno bipolar y las consiguientes pérdidas de sentido de la realidad. De acuerdo con la aproximación metafórica aplicada, se proponen terapias para superar la “crisis” a las que se les aplica la analogía de las nuevas terapias regenerativas, orientadas a la corrección de procesos degenerativos. Entre ellas se incluye la incorporación (trasplante en la marchita política científica de viejos conceptos como los de “gobernanza” y “espacios” que pueden actuar, de nuevo simbólicamente, como elementos troncales (pluripotentes para que sirvan como regeneradores de una gestión política habitualmente apoyada en aproximaciones burocráticas y académicas esencialmente simples y tradicionales.
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Directory of Open Access Journals (Sweden)
Ana Belén Fernández-Cervilla
2013-06-01
Full Text Available OBJECTIVE: Describe the current situation of complementary therapies in nursing education in schools and nursing schools in Spain. METHOD: Descriptive study. Study population all faculties andschools ascribed to Spain. Data collection through observation sheet. Analysis units Curricula. Variables (credits, course type, location, type of therapy. Descriptive analysis of relative and absolute data using Excel spreadsheet. RESULTS: Most of the faculties and schoolsofnursingscrutinized the subject of Complementary Therapies has disappeared and those that aparace is an optional subject. CONCLUSION: Complementary Therapies training in Spain is deficient because it is not collected as a core subject and / or obligatory. The absence of Complementary Therapies in the curriculum, questions such as their value in training, conceptualization which teachers, the impact on quality of care, training of teachers responsible for teaching the subject, as well as the number of credits and the course being in the degree of Grado. OBJETIVO: Describir la situación actual de las Terapias Complementarias en la formación enfermera en las escuelas y facultades de enfermería en España. MÉTODO: estudio observacional descriptivo transversal. Población de estudio todas las facultades, escuelas públicas y adscritas de España. Recolección de datos mediante una ficha de observación. Unidades de análisis los Planes de Estudio. Variables (créditos, tipo de asignatura, ubicación, tipo de terapia. Análisis descriptivo de los datos relativos y absolutos mediante hoja de Excel. RESULTADOS: en la mayoría de las facultades y escuelas escrutadas la asignatura de Terapias Complementarias ha desaparecido y en aquellas que aparece es una asignatura optativa. CONCLUSÍON: la formación en Terapias Complementarias en España es deficiente, debido a que no se recoge como asignatura troncal y/o obligatoria. La ausencia de las Terapias Complementarias en el currículum, plantea
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Energy Technology Data Exchange (ETDEWEB)
Medina, V; Cricco, G; Massari, N; Nunez, M; Martin, G; Mohanad, N; Gutierrez, A; Bergoc, R; Rivera, E [Laboratorio de Radioisotopos, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Junin 956, Buenos Aires (Argentina); Crescenti, E; Croci, M [Instituto de Inmunooncologia, Cordoba 3200, Buenos Aires (Argentina)
2006-07-01
The malignant melanoma is a highly aggressive and potentially lethal type of skin cancer. Previously we have reported that the cellular human lines of melanoma WM35 and M15 are resistant to the ionizing radiation (IR). The histamine (HA) although it has a regulator effect of the cellular proliferation in these lines, it is not capable of to modify the response to the IR like it makes with other malignant cellular lines. To investigate the bases of the radioresistance of the melanoma lines we have studied in the WM35 the production of free radicals of oxygen (ROS), the activity of the antioxidant enzymes and their modifications by action of the IR and of the HA. In studies in vitro the cells were treated with HA 10 {mu}M from 20 hs before being irradiated with a dose of 2 Gy (source {sup 137}Cs, dose rate 7.7 Gy/min). The ROS levels, superoxide anion (O{sub 2}{sup -}) and hydrogen peroxide (H{sub 2}O{sub 2}) its were measured by flow cytometry using fluorescent coloring and the activity of dismutase superoxide (SOD), Catalase (CAT) and Glutathion Peroxidase (GPx) its were determined by spectrophotometric techniques and the protein levels by Western blot. The results indicate that in the cells WM35 the HA increases the production of H{sub 2}O{sub 2} in 96% and it diminishes lightly (17%) the levels of O{sub 2}{sup -} . On the contrary, the IR diminishes the levels of H{sub 2}O-2 in 47% and it increases in 46% those of O{sub 2}{sup -}. In the irradiated cells the HA power the decrease of H{sub 2}O{sub 2} produced by the IR. The variation of the enzymes activity is coincident with these changes in the levels of ROS: the treatment with HA increases the activity of SOD and it diminishes that of CAT in cells without irradiating; on the other hand, in the irradiated cells the HA it diminishes the SOD significantly. On the base of these results we can conclude that the levels of H{sub 2}O{sub 2} are directly related with the sensitivity of the cells WM35 to the IR. The HA is able to modulate the activity of the antioxidant enzymes and the levels of ROS. The IR activates cellular mechanisms that take to the radioresistance of these cells and that its interfere and/modifying the biological response mediated by the HA. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Fukurozaki, Sandra Harumi; Seo, Emilia Satoshi Miyamaru [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)). Centro de Ciencia e Tecnologia de Materiais], e-mail: shfukuro@ipen.br
2004-07-01
To improve the standard of society's quality of life, it is necessary to improve the quality of distributed energy and its inherent services within a sustainability process. Among different technological routes that produce more sustainable energy are the fuel cells - also known as combustible batteries. The Global Environment Facility (GEF) has identified the fuel cells as a potential technology to reduce, in the future, the effect of greenhouse gases in both developed and developing countries. Although there are various types of fuel cells, the most used technology for research studies on fuel cells is the Polymer Electrolyte Fuel Cells (FEMFC). However, economic issues - related to the high cost of the membrane's materials and of the catalysts of groups of platinum metals - are still some of the obstacles that need to be overcome for this technology to be more accessible. There are also socio-environmental aspects related to the impacts caused by the extraction, the use and the destination of these metals. Taking in consideration the challenges of complying with the demands of the market and the society as well as with the growing tendency of more rigid patterns of environmental control, the objective of the present work is to show the tool of environmental management - Life Cycle Assessment (LCA) - and its importance on the pursuit for socio-economic and environmental alternatives feasible to the recycling of the catalysts of platinum of the PEMFC. This way, it intends to collaborate to the progress of the knowledge about environmental and socio-economic subjects related to the productive process of the PEMFC. (author)
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Energy Technology Data Exchange (ETDEWEB)
Dresch, Mauro Andre
2014-07-01
This work has as objective to evaluate anodes and electrolytes in direct ethanol fuel cells (DEFC) operating at high temperature (130 deg C). As anode materials, electrocatalysts based on Pt Sn/C were prepared by Modified Polyol Method with various Pt:Sn atomic ratios. Such methodology promotes self organized electrocatalysts production with narrow particle size distribution and high alloying degree. The electrocatalysts were characterized by XRD, and CO stripping. The results showed that these materials presented high alloying degree and Eonset CO oxidation at lower potential as commercial materials. As electrolyte, Nafion-SiO{sub 2} hybrids were synthesized by sol-gel reaction, by the incorporation of oxide directly into the ionic aggregates of various kinds of Nafion membranes. The synthesis parameter, such sol-gel solvent, membrane thickness and silicon precursor concentration were studied in terms of silica incorporation degree and hybrid mechanical stability. Finally, the optimized anodes and electrolytes were evaluated in DEFC operating at 80 - 130 deg C temperature range. The results showed a significant improvement of the DEFC performance (122 mW cm{sup -2}), resulted from the acceleration of ethanol oxidation reaction rate due to anode material optimization and high temperature operation once the use of hybrids possibilities the increase of temperature without a significant conductivity loses. In this sense, the combination of optimized electrodes and electrolytes are a promising alternative for the development of these devices. (author)
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Energy Technology Data Exchange (ETDEWEB)
Parra-Silva, J.; Silva, A.C.; Mello-Castanho, S.R.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Cerpa, A. [Universidad Europea de Madrid, Madrid (Spain)
2014-07-01
Direct alcohol Fuel cells (DAFC) are interesting to use Brazil for reasons of fuel logistics and availability. The catalysts used in these devices to promote the oxidation of alcohol at the anode need to be fixed on a substrate which must provide high specific surface area, porosity, chemical and thermal resistance, this target can be achieved with the characteristics sepiolite. This paper proposes sepiolite as catalyst support for DAFC. Sepiolite is a phyllosilicate with double layered tetrahedral silicon cells and fibrillar structure. Catalysts (Pt / Sb / Sn) were prepared by cation substitution method and tested by cyclic voltammetry. Techniques as XRD and FT-IR were also used for characterizing materials. Was obtained up to 35 mA / g (Pt) peak current (redox ethanol) indicating the possibility of sepiolite technology development to use un proposed purpose. (author)
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Directory of Open Access Journals (Sweden)
Hilda A. Pérez
1985-12-01
Full Text Available Los ratones BALB/c inmunizados SC con promastigotes no viables de Leishmania mexicana pifanoi, desarrollaron respuestas de hipersensibilidad tardia (RHT contra el parásito. En contraposición, los ratones BALB/c infectados crónicamente con L.m. pifanoi y aquellos inmunizados IV con una dosis supraóptima de parásitos muertos, mostraron inhibición de la RHT. La supresión de la RHT en los animales infectados, estuvo precedida por un estado transitorio de inmunidad celular, manifestado durante la fase inicial del desarrollo de las lesiones (4-12 semanas. La inhibición de la RHT observada en los animales infectados o inmunizados con dosis supraóptimas, fue causada por un mecanismo activo, transferible a receptores singénicos a través de las células esplénicas de los donantes suprimidos. La población de células supresoras fue no adherente a "nylon", sensible al tratamiento con un suero anti-timocitos de ratón y C', y de acción específica sobre la RHT contra antígenos leishmánicos. Se propone que la ocurrencia de células T supresoras de la RHT en los animales infectados crónicamente o inmunizados con dosis supraóptimas, es causada por el exceso de carga antigénica. Esta última, en el caso de los animales infectados, secundaria a una falla primaria en el control inmunológico de la población parasitaria.A T suppressor cell population that specifically shut down delayed hypersensitivity responses (DHR to the parasite was found in both BALB/c mice chronically infected with Leishmania mexicana pifanoi and in naive mice which had received a single IV supraoptimal dose of killed parasites. At the early phase of infection mice exhibited a transitory state of cell-mediated immunity against the parasite that was abrogated when lesions reached their accelerated phase of growth. Results suggest that in both infected and high-dose immunized mice, the activation of T suppressor cells of DHR is related to antigen overload.
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Energy Technology Data Exchange (ETDEWEB)
Oliveira, Paula N.; Pires, Alfredo T.N. [Grupo de Estudo em Materiais Polimericos - POLIMAT - UFSC, Florianopolis, SC (Brazil); Catarino, Margarida; Brandao, Lucia; Tanaka, Alfredo; Mendes, Adelio [Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)
2011-07-01
In the present study, PVA/SSA membranes were prepared with and without the addition of Al{sub 2}O{sub 3} nanoparticles. Sulfosuccinic acid (SSA) was used as the crosslinking agent. Membranes were prepared with different amounts of SSA (26, 43 and 55 wt.%) and with 5 and 10 wt.% of nanoparticles. Crosslinking was performed at 90 degree C during 1.5 h. Membranes were analyzed by infrared spectroscopy, thermal analysis, water absorption, ion exchange capacity (IEC) and proton conductivity. The results showed that control of the crosslinking conditions, IEC value, water absorption and polymer structure are of significant importance to obtain a set of properties suitable for application in proton exchange membrane fuel cells. (author)
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Directory of Open Access Journals (Sweden)
J. Vizcaino
2000-07-01
Full Text Available RESUMO: O Mioblastoma de pulmão é um tumor raro, com origem nas células de Schwann, cujo modo de apresentação mais comum é a tosse e a toracalgia. Pode ser um achado radiológico ou endoscópico.O caso que apresentamos referese a um doente de sexo masculino, 55 anos de idade, carpinteiro, exfumador (52 UMA, com história de bronquite crónica (BC, que referia toracalgia esquerda desde há alguns meses, ouvindo-se na auscultação pulmonar um sibilo fixo na base do hemitórax esquerdo. A telerradiografia do tórax revelou apenas âpaquipleurite residual na base do hemitórax direitoâ. A TAC torácica (com cortes nnos mostrou âdiscreta imagem nodular no apical do lobo inferior esquerdo (B6 e paquipleurite residual na base do hemitórax direitoâ. A broncofibroscopla revelou âsinais de BC e no segmento mais posterior do apical do lobo inferior esquerdo o esporão está um pouco esbranquiçado mas sem outras lesõesâ. Realizou biópsias a este nÃvel que mostraram âtumor de celulas granulares-Mioblastomaâ, pelo que foi submetido a lobectomia inferior esquerda cujo exame anatomopatológico da peça ressecada confirmou o diagnóstico. Desde então, o doente é seguido na nossa consulta mantendo a sua BC controlada e sem qualquer evidência de recidiva tumoral.A propósito fazem-se algumas considerações sobre este tipo de neoplasia do pulmão, cuja histogénese é desconhecida.REV PORT PNEUMOL 2000; VI (4: 323-330 ABSTRACT: Granular Cell Myoblastoma is a very rare lung tumor arising from Schwann cells. Cough and chest pain are the most frequent presenting symptoms. It can be also a X-ray or endoscopic finding.The present case is about a 55 years old carpenter, ex-smoker (52 pack-years, with chronic bronchitis. A left side chest pain lasting for several months was his main complain. A fixed wheeze could be beard on phisical observation
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Life-cycle optimization model for distributed generation in buildings
Safaei, Amir
principal objetivo desta tese de doutoramento foi desenvolver um modelo para otimizar o desenho e operacao de sistemas de GD para o setor da construcao de edificios comerciais em Portugal, considerando os respetivos Impactes de Ciclo de Vida (IAVC) e Custos de Ciclo de Vida (CCV), de modo a satisfazer as necessidades energeticas do edificio. Tres tipos de tecnologias de cogeracao (Micro-Turbinas, Motores de combustao interna, e Celulas combustiveis de Oxido solido), e dois tipos de tecnologias de energia solar, solar termica e fotovoltaica, constituem os sistemas de GD que sao acoplados aos sistemas convencionais. Foi desenvolvido um modelo de CV, tendo em conta todos os impactes relacionados com a construcao e operacao dos sistemas de energia, bem como os processos a montante relacionados com a producao do GN. Em particular, o mix de GN consumido em Portugal em 2011 foi identificado (60% da Nigeria, 40% da Argelia) e os impactes relativos a cada uma das vias de abastecimento foram avaliados separadamente para quatro categorias de impacte ambiental: Consumo de Energia Primaria (CEP), Gases com Efeito de Estufa (GEE), acidificacao, e eutrofizacao. Devido a importancia das emissoes de GEE na formulacao de politicas, foi tambem realizada uma analise de incerteza as emissoes de GEE do GN fornecido a Portugal. Foi desenvolvido um modelo matematico, em linguagem de Programacao General Algebraic Modeling System (GAMS), que utiliza os resultados da ACV dos sistemas de energia e as suas implicacoes economicas para minimizar o CCV e IACV ao longo de um horizonte de planeamento definido pelo decisor. Foram derivadas fronteiras otimas de Pareto, representando as relacoes entre o tipo de IACV (CEP, GEE, acidificacao, eutrofizacao) e CCV decorrentes da satisfacao das necessidades energeticas do edificio. Para aumentar a robustez do modelo, dada a incerteza dos precos dos combustiveis (GN e eletricidade), foi desenvolvido um modelo de custos robusto para os sistemas de GD, que e menos
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Energy Technology Data Exchange (ETDEWEB)
Pelling, C. [Max-Planck-Institut fuer Biologie, Tuebingen, Federal Republic of Germany (Germany)
1962-02-15
des chromosomes semble representee par la synthese de l'ARN, qui se produit en certains 'loci' distincts ('organiseurs' nucleaires, anneaux de Balbiani, nodules et bandes chromosomiques). L'auteur examine certains aspects caracteristiques de la synthese de l'ARN. (author) [Spanish] l.os autores realizaron sus investigaciones con los cromosomas de las glandulas salivares del Ghironomus tentans. La inyeccion do compuestos tritiados (timidina-{sup 3}H, uridina-{sup 3}H, aminoacidos {sup 3}H) en la hemolinfa de las larvas permite determinar en que lugar de los cromosomas gigantes se produce la incorporacion. Una vez fijadas las glandulas salivares, los autores obtuvieron autorradiografias de las preparaciones trituradas. Estas autorradiografias demuestran que los cromosomas gigantes son los mas adecuados para localizar la radiactividad en las estructuras cromosomicas con un grado de resolucion muy elevado. Determinando el tiempo y el grado aproximado de incorporacion, los autores han conseguido seguir en la celula la sintesis del ADN (timidina), del ARN (uridina) y de las proteinas. Las dos primeras tienen lugar exclusivamente en los cromosomas, contrariamente a lo que ocurre para la sintesis de las proteinas. Al parecer, la actividad fisiologica esencial de los cromosomas consiste en la sintesis del ARN, que se produce en ciertos lugares determinados (organizadores nucleares, anillos de Balbiani, y otras bandas cromosomicas). La memoria discute algunos aspectos de la sintesis del ARN. (author) [Russian] Provo- dilis' issledovanija hromosom sljunnoj zhelezy Chironomus tentans. Tretiro- vannye soedinenija ({sup 3}N-timidin, {sup 3}N-uridin, {sup 3}N-aminokisloty), vvedennye v gemolimf lichinki, dolzhny ukazyvat' mesta pogloshhenija v bol'shih hromosomah. Posle fiksacii sljunnyh zhelez byli sdelany radioavtogrammy mjagkoj massy. Radioavtogrammy pokazyvajut, chto bol'shie hromosomy javljajutsja bolee pod- hodjashhimi dlja lokalizacii aktivnosti u hromosomnyh struktur s
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Energy Technology Data Exchange (ETDEWEB)
Lopes, Daniel Gabriel; Furlan, Andre Luis; Lopes, Davi Gabriel [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica], e-mail: danielg@fem.unicamp.br; Silva, Ennio Peres; Apolinario, Fernando Resende [Universidade Estadual de Campinas (IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Lab. de Hidrogenio; Silva, Maria Eugenia Vieira da; Rocha, Paulo Alexandre Costa [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Mecanica e de Producao; Codeceira Neto, Alcides [Companhia Hidro Eletrica do Sao Francisco (CHESF), Recife, PE (Brazil)
2008-07-01
Due to relevance of the study and applicability of hybrid electric power generation from solar photovoltaic and wind power in Brazil, the present paper aims to introduce briefly the importance of technical and economic comparison of two electrical energy storage technologies (batteries versus H2 + fuel cell) and also to indicate the previous difficulties related to this possible application. In this context, it was intended a partnership between State University of Campinas - UNICAMP, the Federal University of Ceara - UFC and Hydro Electric Company of the Sao Francisco - CHESF in the meaning of makes viable an implementation. (author)
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Energy Technology Data Exchange (ETDEWEB)
Quarneti, A.; Alonso, O.; De Rosa, A.; García Fontes, M.; Luongo Gardi, A.; Castillo, C.; Delgado, L.; Pintado, D.; Dalla Rossa, M.; Guerrero, L.; Lillo, O.; Luongo Gardi, M.; Castaño, A.; Luongo, A.; De Trapani, E.; Torres, M. [Departamentos de Oncología, Imagenología, Medicina Nuclear del Hospital de Clínicas, Facultad de Medicina, Montevideo (Uruguay)
2010-12-15
Full text: However there are few clinical situations that allow treatment appropriate surgical. Chemoradiation treatment has shown results above, however the amount of radiation treatment in general is large, determines morbidity and limited in part to receive the final dose as already reported in previous Congresses Uruguayans Oncology 2000 and 2002 where it rarely Local control was obtained. They inform you of the need to limit treatment volumes radiant disease or biological tumor volume (VTB) using complementary imaging procedures. Objective: To determine the radiation treatment volumes contributing MIBI clarify the VTB. Compare those figures with those established by the TAC. To analyze the intra and extra faults VTB and analyze treatment with RT type ''Involved Field'' or involved field RT (IF) Materrial and Methods: This project Conclusions: This proposal identifies problems and opportunities, proposes institutional development of the SOR network under one management model.
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Energy Technology Data Exchange (ETDEWEB)
Sanchez H, L.
2014-07-01
The conjugation of peptides to gold nanoparticles (AuNP) produces biocompatible and stable multimeric systems with target-specific molecular recognition. Peptides based on the cyclic Arg-Gly-Asp (RGD) sequence have been reported as high-affinity agents for the α(v)β(3) and α(v)β(v) integrin s over expressed in breast cancer cells. AuNP have also been proposed as localized heat sources for cancer treatment using laser irradiation or radiofrequency (RF). The objective of this research was to evaluate the thermo ablative effect of the AuNP-c [RGDfK(C)] system on MCF7 breast cancer cell viability after exposure to a radiofrequency field and to compare it with that produced by the laser irradiation. The effect of the 13.56 MHz RF (using a power from 0 to 200 W at intervals of 50 W) over the temperature increase in AuNP-colloidal system of 5 and 20 nm at two different concentrations was evaluated. The absorption cross sections (C{sub abs}) of the AuNP-c [RGDfK(C)] nano system when it interacts with low frequency electromagnetic waves (13.56 MHz, λ = 22 m) and optical frequency waves (laser at λ = 532 nm) was analyzed based on the Mi e theory. The effect on the MCF7 cell viability was assessed using two thermal conversion sources (Laser and RF) on AuNP-c [RGDfK(C)] located inside the cytoplasm of the cells. MCF7 cells were treated with AuNP-c [RGDfK(C)] or water after exposure to the RF field (200 W, 100 V/cm) or laser irradiation (Irradiance 0.65 W/cm{sup 2}). In both cases (RF and laser) the presence of nanoparticles internalized inside the cells caused a significant increase in the temperature of the medium (RF: ΔT = 29.9 ± 1.7 grades C for AuNP compared toΔT = 13.0 ± 1.4 grades C for water; laser: ΔT = 13.5 ± 0.7 grades C for AuNP compared to 3.3 ± 0.5 grades C for water). Although RF induced a higher increase in the temperature of the medium with nanoparticles, the largest effect on the cell viability was produced by laser when nanoparticles were located inside the cells (8.7 ± 0.7 % for laser compared to 19.4 ± 0.9 % for RF). The differences obtained in C{sub abs} values (laser: 3.7x10{sup -16} m{sup 2}; RF: 7.9x10{sup -23} m{sup 2}) and the observed effect on MCF7 cell viability support two mechanisms proposed -optical frequency wave energy absorption by AuNP- when laser is used as a thermal conversion source, and -energy attenuation of the low frequency electromagnetic wave propagating through the AuNP-colloidal system- when RF field is applied. The AuNP-c[RGDfK(C)] nano system shows suitable properties to improve hyperthermia treatments under laser irradiation due to a larger heat release inside cells. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Bollero, A.; Trigo, J. F.; Herrero, J.; Gutierrez, M. T.
2008-07-01
The Department of energy of CIEMAT focuses one of its research lines on the preparation of CuInS{sub 2} films to be used as absorber in solar cells. this work shows the influence of the different process parameters (deposition sequence, modulation of the evaporation flux of the constituent elements,...) on the morphology and the optical properties of the final films. A simplified evaporation procedure has allowed the preparation of CuInS{sub 2} films with a low Cu content. this avoids the necessity of applying subsequent toxic treatment for removal of the CuS phase prior to implementation of the film as absorber in the solar cell device. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Pimentel, A.E.; Cruces, M.P.; Zimmering, S.I. [Departamento de Biologia, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)
2000-07-01
The irradiation of the individuals that had been feed during 24 hours with a chlorophyllin solution at 5 % was delayed from 0 until 4 days. The protector effect of chlorophyllin persisted by 3 days and it appears to coincide with the stage when stopping the mitotic divisions in the imagal disk. Within of the same cellular population, it was demonstrated that chlorophyllin can function as an inhibitor, in the case of simple stains mwh or a potentiator in the case of twin stains and the flr type stains. It was planned an explanation for these results. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Gomes, Thiago Bueno
2013-07-01
The complexity of the oxygen reduction reaction (ORR) and its potential losses make it responsible for the most part of efficiency losses at the Fuel Cells. For this reaction the electrocatalyst witch is most appropriated and shows better performance is platinum, a noble metal that elevates the cost, raising barriers for Fuel Cells technology to enter the market. First this work focuses on reducing the amount of platinum used in the cathode, by being replaced by rare earths. The most common methods of synthesis involves a large amount of steps and this work proposed to prepare the electrocatalyst through a simpler way that would not take so many steps and time to be done. Using an ultrasound mixer the electrocatalyst was prepared mixing platinum supported on carbon black and the rare earths lanthanum, cerium and erbium oxides to be applied in a half-cell study of the ORR. The Koutecky-Levich plots shows that among the electrocatalysts prepared the Pt80Ce20/C had the catalytic activity close to the commercial BASF platinum on carbon black, suggesting that the reaction was taken by the 4-electron path. As found in some works in literature, among the rare earth used to study the ORR, cerium is the one witch shows the better performance because it is able to store and provide oxygen. This feature is of great interest for the ORR because this reaction is first order to the oxygen concentration. Results show that is possible to reduce the amount of platinum maintaining the same electrocatalyst activity. (author)
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Energy Technology Data Exchange (ETDEWEB)
Lopes, Francisco da Costa; Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues da; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: fcl@cepel.br
2008-07-01
Fuel cell based power generation systems have been pointing as promising technology for stationary applications mainly to supply power to critical loads. Among several types of fuel cells the Polymer Electrolyte Membrane Fuel Cells (PEMFC) are the main type used around the world. Nowadays reformers are widely employed to produce hydrogen for fuel cells. The Fuel Cell Laboratory of CEPEL has a power plant based on a 5 kW PEMFC and a natural gas reformer. For a long time the PEMFC was inoperable due to reformer malfunctioning and during this time the full power availability of PEMFC was lost due to deactivation of its catalytic sites. In most cases this deactivation is reversible. So it was started a reactivation process aiming to recover the full operational condition of the PEMFC unit. During this process the gas flow relationship and efficiency of the reformer were studied. An analysis of the PEMFC reactivation was conducted where it was noted that the reactivation took place as expected. During the reactivation process the PEMFC and the whole system efficiency were analyzed. The results suggest that the PEMFC can reach efficiency compatible with conventional power generation systems thus allowing PEMFC technology to compete with these energy sources in point of efficiency. (author)
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Energy Technology Data Exchange (ETDEWEB)
Bonifacio, Rafael Nogueira
2010-07-01
Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants' emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of k W of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm{sup -2}) suitable for cathodes and 0.4 mgPt.cm{sup -2} for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 m A.cm{sup -2} by 600 mV to 25 cm{sup 2} MEA area. The MEA cost production for MEAs of 247.86 cm{sup 2}, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)
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Energy Technology Data Exchange (ETDEWEB)
Yoshito, Daniele
2011-07-01
For over 30 years, the use of culture medium, enriched with bovine serum, and murines fibroblasts, with the rate of proliferation controlled by irradiation or by share anticarcinogenic drugs, has been playing successfully its role in assisting in the development of keratinocytes in culture, for clinical purposes. However, currently there is a growing concern about the possibility of transmitting prions and animals viruses to transplanted patients. Taking into account this concern, the present work aims to cultivate human fibroblasts in a medium enriched with human platelets lysate and determine the irradiation dose of these cells, for obtaining feeder layer in epidermal cell culture. For carrying out the proposed objective, platelets lysis has standardized, this lysate was used for human fibroblasts cultivation and the irradiation dose enough to inhibit its duplication was evaluated. Human keratinocytes were cultivated in these feeder layers, in culture medium enriched with the lysate. With these results we conclude that the 10% platelets lysate promoted a better adhesion and proliferation of human fibroblasts and in all dose levels tested (60 to 300 Gy), these had their mitotic activity inactivated by ionizing irradiation, being that the feeder layers obtained with doses from 70 to 150 Gy were those that provided the best development of keratinocytes in medium containing 2.5% of human platelet lysate. Therefore, it was possible to standardize both the cultivation of human fibroblasts as its inactivation for use as feeder layer in culture of keratinocytes, so as to eliminate xenobiotics components. (author)
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Energy Technology Data Exchange (ETDEWEB)
Gambetta, Francielle [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mail: fgambetta@fem.unicamp.br; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica. Lab. de Hidrogenio
2008-07-01
Due the fact that consumers have different demand, depending on the pace of economic activities and their daily habits of consumption, there is a different electrical demand throughout the day. Demand, in general, is minimal during the morning and it grows with the move for hours to reach peak consumption between 18:00 and 22:00, then turning to fall. It is old the idea of storing electricity produced in off-peak for its consumption in peak hours. To store large amounts of electrical power is required its conversion into some other form of energy, since it is impossible to store electrical energy as such in large quantities. One way of storing electricity is in the form of hydrogen produced by electrolysis of water which then can be stored, purified and converted into electricity through fuel cells. When there is an increase in demand for electricity, there is a need to expand the supply of energy, which means investments in generation, transmission and distribution. This work was performed a preliminary analysis of the production of electrolytic hydrogen in hours of low demand and its use in the generation of electricity in peak hours, making use of the fuel cells, so that to a certain limit value of increased electricity demand, there is no need for expansion of supply of Foz do Iguacu/PR. Moreover, at this work, the ability to harness the heat generated in fuel cells for heating water in homes was considered. (author)
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Energy Technology Data Exchange (ETDEWEB)
Cunha, Edgar Ferrari da
2009-07-01
This work is part of a research project on PEMFC technologies carried out in IPEN to develop and optimize a 500 W{sub e} fuel cell stack. The MEAs scaling up from 25 cm{sup 2} to 144 cm{sup 2} produced by the method of sieve printing; computational fluid dynamics by computer simulation of gas flow channels in bipolar plates using COMSOL{sup R} program and the use of Pt/C electrodes developed by alcohol reduction method in single cells were used to build a stack of 500 W{sub e} nominal power for possible commercial applications, produced with national technology and industrial support. A 100 hours fuel cell's test was carried out in a 144 cm{sup 2} single cell to study the stability of the MEA fabricated by sieve printing method. This single cell showed good stability within this period of time. The developed stack has reached the maximum power of 574 W{sub e} at 100 A (694.4 mA cm{sup -2}). The operating power of 500 W{sub e} was obtained at 77.7 A (540.1 mA cm{sup -2}) and potential of 6.43 V, with efficiency of 43.3%. In terms of cogeneration, the thermal power or generated heat by the stack was 652 W{sub t}. The initial estimated cost for the 500 W{sub e} stack was about R$ 4,500.00, considering only the used materials for its construction. (author)
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Energy Technology Data Exchange (ETDEWEB)
Mamani, Javier Bustamante; Pavon, Lorena Favaro; Sibov, Tatiana Tais; Rossan, Fabiana; Silveira, Paulo Henrique; Cardenas, Walter Humberto; Gamarra, Lionel Fernel, E-mail: javierbm@einstein.br [Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Miyaki, Liza Aya Mabuchi [Faculdade de Enfermagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Amaro Junior, Edson [Departamento de Diagnostico por Imagem e Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil)
2012-04-15
Objective: To assess intracellular labeling and quantification by magnetic resonance imaging using iron oxide magnetic nanoparticles coated with biocompatible materials in rat C6 glioma cells in vitro. These methods will provide direction for future trials of tumor induction in vivo as well as possible magnetic hyperthermia applications. Methods: Aminosilane, dextran, polyvinyl alcohol, and starch-coated magnetic nanoparticles were used in the qualitative assessment of C6 cell labeling via light microscopy. The influence of the transfection agent poly-L-lysine on cellular uptake was examined. The quantification process was performed by relaxometry analysis in T{sub 1} and T{sub 2} weighted phantom images. Results: Light microscopy revealed that the aminosilane-coated magnetic nanoparticles alone or complexed with poly-L-lysine showed higher cellular uptake than did the uncoated magnetic particles. The relaxactivities of the aminosilane-coated magnetic nanoparticles with a hydrodynamic diameter of 50nm to a 3-T field were r{sub 1}=(6.1 +- 0.3) x10{sup -5} ms{sup -1}mL/{mu}g, r{sub 2}=(5.3 +- 0.1) x 10{sup -4} ms{sup -1}mL/{mu}g, with a ratio of r{sub 2} / r{sub 1}{approx_equal} 9. The iron uptake in the cells was calculated by analyzing the relaxation rates (R{sub 1}and R{sub 2}) using a mathematical relationship. Conclusions: C6 glioma cells have a high uptake efficiency for aminosilane-coated magnetic nanoparticles complexed with the transfection agent poly-L-lysine. The large ratio r{sub 2} / r{sub 1}{approx_equal} 9 indicates that these magnetic nanoparticles are ideal for quantification by magnetic resonance imaging with T{sub 2}-weighted imaging techniques. (author)
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Energy Technology Data Exchange (ETDEWEB)
Sibov, Tatiana Tais; Mamani, Javier Bustamante; Pavon, Lorena Favaro; Cardenas, Walter Humberto; Gamarra, Lionel Fernel, E-mail: tatianats@einstein.br [Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Miyaki, Liza Aya Mabuchi [Faculdade de Enfermagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Marti, Luciana Cavalheiro; Sardinha, Luiz Roberto [Centro de Pesquisa Experimental, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Oliveira, Daniela Mara de [Universidade de Brasilia - UnB, Brasilia, DF (Brazil)
2012-04-15
Objective: The objective of this study was to evaluate the effect of the labeling of umbilical cord vein derived mesenchymal stem cells with superparamagnetic iron oxide nanoparticles coated with dextran and complexed to a non-viral transfector agent transfector poly-L-lysine. Methods: The labeling of mesenchymal stem cells was performed using the superparamagnetic iron oxide nanoparticles/dextran complexed and not complexed to poly-L-lysine. Superparamagnetic iron oxide nanoparticles/dextran was incubated with poly-L-lysine in an ultrasonic sonicator at 37 deg C for 10 minutes for complex formation superparamagnetic iron oxide nanoparticles/dextran/poly-L-lysine by electrostatic interaction. Then, the mesenchymal stem cells were incubated overnight with the complex superparamagnetic iron oxide nanoparticles/dextran/poly-L-lysine and superparamagnetic iron oxide nanoparticles/dextran. After the incubation period the mesenchymal stem cells were evaluated by internalization of the complex superparamagnetic iron oxide nanoparticles/dextran/polyL-lysine and superparamagnetic iron oxide nanoparticles/dextran by Prussian Blue stain. Cellular viability of labeled mesenchymal stem cells was evaluated by cellular proliferation assay using 5,6-carboxyfluorescein-succinimidyl ester method and apoptosis detection by Annexin V- Propidium Iodide assay. Results: mesenchymal stem cells labeled with superparamagnetic iron oxide nanoparticles/ dextran without poly-L-lysine not internalized efficiently the superparamagnetic iron oxide nanoparticles due to its low presence detected within cells. Mesenchymal stem cells labeled with the complex superparamagnetic iron oxide nanoparticles/dextran/polyL-lysine efficiently internalized the superparamagnetic iron oxide nanoparticles due to greater presence in the cells interior. The viability and apoptosis assays demonstrated that the mesenchymal stem cells labeled and not labeled respectively with the superparamagnetic iron oxide nanoparticles/dextran/poly-L-lysine continue to proliferate over seven days and the percentage of cells in early or late apoptosis is low compared to the percentage of live cells over the three days. Conclusion: Our results showed that the use of poly-L-lysine complexed with superparamagnetic iron oxide nanoparticles/dextran provides better internalization of these superparamagnetic iron oxide nanoparticles in mesenchymal stem cells Thus, we demonstrated that this type of labeling is not cytotoxic to the mesenchymal stem cells, since the viability and apoptosis assays showed that the cells remain alive and proliferating. The efficiency of this type of labeling in mesenchymal stem cells can provide non-invasive methods for monitoring these cells in vivo. (author)
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Energy Technology Data Exchange (ETDEWEB)
Cunha, Edgar Ferrari da
2009-07-01
This work is part of a research project on PEMFC technologies carried out in IPEN to develop and optimize a 500 W{sub e} fuel cell stack. The MEAs scaling up from 25 cm{sup 2} to 144 cm{sup 2} produced by the method of sieve printing; computational fluid dynamics by computer simulation of gas flow channels in bipolar plates using COMSOL{sup R} program and the use of Pt/C electrodes developed by alcohol reduction method in single cells were used to build a stack of 500 W{sub e} nominal power for possible commercial applications, produced with national technology and industrial support. A 100 hours fuel cell's test was carried out in a 144 cm{sup 2} single cell to study the stability of the MEA fabricated by sieve printing method. This single cell showed good stability within this period of time. The developed stack has reached the maximum power of 574 W{sub e} at 100 A (694.4 mA cm{sup -2}). The operating power of 500 W{sub e} was obtained at 77.7 A (540.1 mA cm{sup -2}) and potential of 6.43 V, with efficiency of 43.3%. In terms of cogeneration, the thermal power or generated heat by the stack was 652 W{sub t}. The initial estimated cost for the 500 W{sub e} stack was about R$ 4,500.00, considering only the used materials for its construction. (author)
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Energy Technology Data Exchange (ETDEWEB)
Morales R, P.; Cruz V, V.L. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico). Dept. de Biologia
1997-07-01
The effect of {beta}- carotene over the ICH radioinduction in radiosensibilized with BrdU osseous marrow cells of mouse was determined In vivo. The treatment with 50 {mu}g {beta} carotene per se induces a significant increment in the ICH frequency and the pre or post-treatment with the same dose causes an additive effect in the ICH frequency produced by 0.62 Gy of gamma radiation. This implies that {beta}- carotene does not have radioprotective activity, under conditions which was developed this experiment. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Orocio R, E.
2013-07-01
The objective of this project was preparing a multimeric system through the conjugation of several molecules of the peptide Tyr{sup 3}-Octreotide to a dendrimer molecule based on Poly-amidoamine (PAMAM), as well as radiolabeled with {sup 99m}Tc and evaluating its behavior like new radiopharmaceutical similar of somatostatin. The dendrimer PAMAM generation 3.5 that possesses terminal groups of sodium carboxylate, was functionalized to peptide Tyr{sup 3}-Octreotide through a reaction of peptide coupling with HATU (hexafluorophosphate (V) of 1-oxide-3-(bis(dimethylamino)methylene)-3H-[1,2,3]triazole[4,5-b]pyridine) as activating agent of carboxylate groups using the Size Exclusion Chromatography (Sec) as purification method. The product was characterized by Ultraviolet visible spectrophotometry, Mid-infrared and Far-infrared, Elemental analysis, Energy dispersive X-ray spectroscopy, Scanning electron microscopy, Thermogravimetry and Differential scanning calorimetry. The radiolabeled with {sup 99m}Tc was carried out using a direct method that involves the reduction of the anion TcO{sub 4}{sup -} with stannous chloride, so that the dendrimer is capable of coordinating to the technetium forming a chelate compound. The radiochemical purity of the radiolabeled compound was determined by thin layer chromatography using a sodium chloride solution to 20% (m/v) as mobile phase and was verified by molecular exclusion chromatography. The radiolabeled compound was possible to obtain it with a radiochemical purity superior to 90%. Also, the specific and not specific union was evaluated of the synthesized compound in mouse pancreas cancer cells AR42J, positive to somatostatin receptors, showing specific recognition for this receptors type with high cellular internalization. The biodistribution studies were carried out in BALB/c mice at different post injection times and in nude mice with induced tumors AR42J. The results showed that the {sup 99m}Tc-PAMAM-Tyr{sup 3}-Octreotide is excreted by via renal as hepatobiliary with a tumor capture of 4.12±0.6 D.I.g{sup -1} at the two hours of having been administered, which shows their potential as new radiopharmaceutical similar of somatostatin for the tumors detection of neuroendocrine origin. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Alcantara D, D [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)
1987-05-15
The objective of this work is to determine the paper of the genes ruvA and recN in the stimulation of the recombination of Lambda for UV irradiation of Escherichia Coli, taking into account that both genes are inducible, they belong to the group of genes that participate in the SOS response and that a deficiency in its expression reduces the capacity to repair and recombiner the DNA. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Blanco, P.H.L.; Muccillo, R.; Muccillo, E.N.S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: enavarro@usp.br
2008-07-01
Solid oxide fuel cells are basically constituted by ceramic materials, a solid electrolyte sandwiched between two electrodes. A number of ceramic materials with perovskite structure have been proposed to act as electrode material due to the combination of their physical and chemical properties along with compatibility with the solid electrolyte. In this work the mixed oxide Sm{sub 0,5}Sr{sub 0,5}CoO{sub 3} was synthesized by the cation complexation technique. This perovskite oxide has been proposed as cathode in solid oxide fuel cells that operates in the intermediate temperature range ({approx} 500 to {approx} 700 deg C). Citric acid was used as complexant agent. The thermal decomposition of the precursor material occurs in several stages up to 600 deg C. After calcinations at 700 deg C the mixed oxide exhibits the characteristic perovskite phase of Sm{sub 0,5} Sr{sub 0,5}CoO{sub 3} the microstructure of the thermally decomposed material consists of porous agglomerates. This technique allowed for obtaining a single phase material at a relatively lower temperature. (author)
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Energy Technology Data Exchange (ETDEWEB)
Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de, E-mail: gabriela.galvao@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)
2016-07-01
Mixed oxide ceramics with chemical structure of ABO{sub 3} type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO{sub 3} and La{sub 0,2}Sr{sub 0,8}CoO{sub 3} perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)
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Energy Technology Data Exchange (ETDEWEB)
Lopes, Davi Gabriel; Teixeira, Andre Frazao; Lopes, Daniel Gabriel; Cavaliero, Carla Kazue Nakao [Universidade Estadual de Campinas (DE/FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Departamento de Energia; Instituto Aqua Genesis, Campinas, SP (Brazil); Hytron, Campinas, SP (Brazil)
2010-07-01
This work has the objective to analyze the impact of the cost of from an ethane reformer / fuel cell in the family income considering the development of two productive activities selected by the community itself: the production and marketing of cassava flour and 'rapadura', a typical brazilian candy. The community energy demand was analyzed to achieve the results; estimated the energy cost from the implemented system and the money from the selling of the cassava flour and 'rapadura' produced with this electricity; the study of sensibility of the ethanol price in the electrical energy cost was done too, and the cassava flour and 'rapadura' in the family funds. From the results, it was verified that the electrical energy cost has a 16,4% impact in the family gross income and a net value around R$ 260,85/family, indicating that the community will have enough funds to pay for the energy and also will rise the amount of money for each family. Besides, the comparative analyze of the cost of the electricity from the ethanol/fuel cell reformer and photovoltaic systems shows that, considering only the maintenance and operation costs, the first one should be more attractive than the second one. (author)
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Linfoma B Difuso de Grandes Células Esclerosante do Mediastino
Directory of Open Access Journals (Sweden)
Ma. Teresa Magalhães Godinho
2001-03-01
Full Text Available RESUMO: Objectivos: Estabelecer a apresentação clÃnica, diagnóstico, tratamento e prognóstico do linfoma B difuso de grandes células esclerosante do mediastino. Apesar de conhecido dcsde 1980, este linfoma B de alto grau de malignidade com origem no timo, e, ainda hoje, muitas vezes confundido com tumores germinativos, carcinoma do timo, ou Doença de Hodgkin e correlacionado com urn mau prognóstico. Métodos: Revisão de 12 doentes com Linfoma difuso de grandcs células do mediastino anterior, diagnosticados no nosso Seniço entre 1993 e Junho de 2000. Resultados: O grupo é constituido por 10 mulheres e 2 homens, com idades compreendidas entre os 17 e os 59 anos (média 28; mediana 24. Todos os doentes cram sintomaticos. A radiografia do tórax mostrava uma massa de grandes dimcnsões, situada no mediastino anterior, por vezes acompanhada de derrame pleural (4 docntes e/ou pericárdico (2 doentes. Na TAC tonácica, eram visÃveis áreas de atenuação hfdrica e de necrose. Três doentes fueram Ressonancia Magnética do tórax. Analiticamente, estes casos caracterizaram-se por valores elevados da LDH sérica, com β2 microglobulina normal. As biópsias foram realizadas por mediastinotomia anterior em 9 doentes e por toracotomia lateral nos outros 3. Anatomo-patologicamente foram identificados aspectos caracterÃsticos dos Linfomas difusos de grandes cclulas com esclerose e a origem B confirmada por imuno-histoquÃmica. Os doentes foram submctidos a Quimioterapia (CHOP e Radioterapia (35-45 Gy. A taxa de remissao completa foi de 75%. Nove doentes estao vivos e Iivres de doença 6 meses a 7 anos após o diagnostico.Conclusão: 0 Linfoma difuso de grandes celulas esclerosante do mediastino apresenta-se como urn tumor volumoso do mediastino anterior, essencialmente na mulher jovem. Os doentes sao habitualmente sintomaticos. A radiografia de torax e a TAC mostram uma massa
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Applications of hydrogen peroxide in electrochemical technology
Energy Technology Data Exchange (ETDEWEB)
Alvarez Gallegos, Alberto Armando
1998-12-01
oxigeno (COD) fue agotada a niveles por arriba del 85%, indicando una mineralizacion completa de los agentes contaminantes organicos. La vida promedio de del catodo vitreo reticulado de carbon se demostro que era mayor que las 1000 horas durante dos y medio anos de experimentos. Durante este tiempo el funcionamiento del catodo fue muy bueno, conduciendo a resultados reproducibles e indicando que bajo las condiciones experimentales estudiadas el catodo de carbon vitreo reticulado y los componentes de la celula eran quimicamente y electroquimicamente estables.
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Energy Technology Data Exchange (ETDEWEB)
Cuaron, A.; Ortiz-Quezada, F.; Gordon, F.; Trevino, H. [Hospital General del Centro Medico Nacional, IMSS, Mexico D.F. (Mexico)
1969-05-15
procedimiento aqui descrito puede ser empleado como una prueba filtro de la hipertension arterial de origen renovascular, pues ofrece un indice correlacionado en forma directa con el flujo plasmatico renal individual y una serie de imagenes representativas del flujo sanguineo regional en cada uno de los rinones. Como la concentracion renal de la cloromerodrina requiere tanto de un buen flujo sanguineo renal como de la eficiencia de la celula tubular, en los casos de necrosis tubular unilateral se obtendran resultados similares a los obtenidos en los casos de isquemia renal unilateral. En el estudio de la hipertension arterial creemos que el estudio centelleografico necesita ir acompanado del trazado de una curva de concentracion renal de la cloromerodrina para evitar posibles errores causados por diferentes geometrias de ambos rinones con respecto al detector. (author)
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Energy Technology Data Exchange (ETDEWEB)
Profeti, Demetrius; Colmati, Flavio; Carlindo, Adao A.J.; Paganin, Valdecir A.; Gonzalez, Ernesto R.; Ticianelli, Edson A. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: dprofeti@iqsc.usp.br
2008-07-01
The performance of a proton exchange membrane fuel cell (PEMFC) was investigated with the aim at characterizing the effects of the Nafion. content on the scale-up of the electrodes from 5 to 50 cm{sup 2}. It is observed that a diminution of the single cell performance occurred when the electrode area is increased from 5 to 50 cm{sup 2}. The tests carried out with different Nafion. contents, and fuel cell and humidifiers at the same temperature (T{sub cell}=T{sub H2}=T{sub air}=70 deg C) showed a slightly decrease of the fuel cell performance compared to the tests performed at different temperatures (T{sub cell}=70 deg C, T{sub H2}=85 deg C, T{sub air}=75 deg C). In the study of the variation on the Nafion. contents, the higher performance up to a current density of 0.8 A cm-2 is obtained with the 35.5 wt.% Nafion.. On the other hand, at higher current densities values, the performance of the fuel cells is very similar for the 31.0, 35.5 and 39.4 wt.% Nafion contents. (author)
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Energy Technology Data Exchange (ETDEWEB)
Colturato, Maria Tereza
2005-07-01
In the progress of the Nuclear Medicine, many protein based radiopharmaceuticals have been developed in the last years using antibodies and, more recently, biologically active natural peptides or similar synthetic peptides. In the search for agents with specificity for the target tissue in tumors detection, it was verified that small sequences of amino acids may interact with selective sites, with homogenous distribution, fast accumulation in tissues and fast blood clearance when compared to the antibodies. Among the peptides used in the diagnosis of tumors, Vasoactive Intestinal Peptide (VIP) has been studied. VIP labeled with iodine-123 is applied in the images of intestinal adenocarcinoma and endocrine tumors. The molecule of VIP contains two tyrosine residues, in the positions 10 and 22 that are, theoretically, equally susceptible to radioiodination for direct method. The objective of this work was to produce VIP labeled with radioiodine (iodine-123), in order to introduce to the brazilian medical class this radiopharmaceutical of interest for the diagnosis and recurrence of tumors that express specific receptors. In an unpublished way, the work studied the labeling and the kinetic distribution of the VIP fragment (VIP 10-28) and verified its potential as radiopharmaceutical applied in the identification of tumors that express VIP receptors. After the choice of the appropriated technique for labeling VIP and VIP 10-28 with radioiodine, using Ceremonial T as oxidant agent and sodium metabisulfite as reducing agent, the quality control procedures were accomplished (electrophoresis and high performance liquid chromatography, HPLC) for radiochemical purity determination as well as the separation of the radiochemical species obtained. Labeling and quality control procedures applied were efficient and accurate. [{sup 131}I]VIP and [{sup 131}l]VIP 10-28 were obtained with high radiochemical purity (> 95%). The purification studies to remove free radioiodine in the labeling mixture (simple purification) and to produce the radiopharmaceutical with high specific activity (complex purification and HPLC), were both efficient in the separation of the species in the reaction mixtures, as demonstrated by quality control procedures. Biological distribution studies were accomplished by venous administration of the radiopharmaceuticals in laboratory animals: biodistribution study of [{sup 131}I]VIP and [{sup 131}I]VIP 10-28 in normal Swiss mice, [{sup 131}I]VIP not purified and purified in Swiss mice with tumor and [{sup 131}I]VIP and [{sup 131}I]VIP 10-28 in Nude mice with tumor, scintigraphic images of [{sup 131/123}I]VIP and [{sup 123}I]VIP 10-28 in Swiss and Nude mice and Wistar rats with tumor. In vitro studies were accomplished to determine the percentage of [{sup 131}I]VIP and [{sup 131}I]VIP 10-28 bound to plasmatic proteins, stability study of [{sup 131}I]VIP and [{sup 131}I]VIP 10-28 in human plasma and the affinity and internalization of [{sup 131}I]VIP and [{sup 131}I]VIP 10-28 by tumour adenocarcinoma cells of human rectal colon (HT-29). All biological distribution studies demonstrated that both [{sup 131/123}I]VIP and [{sup 131/123}I]VIP 10-28 showed fast blood clearance, low renal and liver uptake, relative uptake in thyroid, showing in vivo dehalogenation and good uptake in tumour. Comparative biological distribution of the radiopharmaceuticals showed high uptake in the stomach for both peptides. The blood clearance of the fragment was slower, and influences the visualization of the tumour mass. The radiopharmaceuticals, [{sup 123}I]VIP and [{sup 123}I]VIP 10-28, were obtained with high radiochemical purity, but with low radiochemical yield when comparing with labeling procedures using iodine-131. Quality control assays of [{sup 123}I]Na indicated that the presence of radiochemical and radionuclide impurities influenced on labeling results. (author)
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Energy Technology Data Exchange (ETDEWEB)
Araujo, Paula Duarte; Bergamini, Cristiane Peres; Camargo, Joao Carlos; Lopes, Daniel Gabriel [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Mecanica; Esteves, Gheisa Roberta Telles [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Nucleo de Pesquisas e Estudos Ambientais; Silva, Ennio Peres da Silva [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin
2004-07-01
Although great part of the domestic territory is already supplied with electric energy, still there are many regions where the system is precarious or nonexistent, generically called isolated communities. In the majority of the cases these communities are supplied with Diesel oil generators and the substitution of this fuel for available alternative energy in the localities has been object of study of some institutions of research spread throughout the country. Currently, the use of fuel cells has been strongly argued in the generation of electric energy associated with the local energy necessity, from the use of a regional fuel and this is due to the high efficiency of allied energy conversion to the low ambient impacts that this equipment offers. Most of the different types of fuel cells use hydrogen as a fuel to produce electricity, and it is extracted from renewable or non-renewable sources of energy. Then, the article has the objective of comparing in first analysis the energy efficiency and the cost between the two systems: the ones used currently in the great majority of the isolated communities, constituted of a Diesel engine-generator system, with Natural Gas Reformer System/ Purifier of Hydrogen/ Fuel Cell/ and to analyze if such project presents characteristics that qualifies it to get the carbon credits proposed in the Mechanism of Clean Development. (author)
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Energy Technology Data Exchange (ETDEWEB)
Tarrago, D.P.; Sousa, V.C., E-mail: dptarrago@gmail.co [Universidade Federal do Rio Grande do Sul (LABIOMAT/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos graduacao em Engenharia de Minas. Lab. de Biomateriais; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul (LAPEC/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos graduacao em Engenharia de Minas. Lab. de Pesquisa em Corrosao
2010-07-01
Perovskite powders, with composition La{sub 1-x}Sr{sub x}MnO{sub 3} (x=0,1) were obtained via combustion synthesis using sucrose as fuel. In the X-ray diffraction patterns it was observed that in order to obtain a single phase and well crystallized material a calcination in 750 deg C for 3 hours was necessary. BET analysis detected a specific surface area of 45m{sup 2}/g, considerably higher than when obtained with other fuels. SEM micrographs revealed a spongy aspect with a connected porosity in the agglomerates and though TEM micrographs the presence of pores in the particles was verified. The powder compacted with 125MPa and sintered at 1050 deg C for two hours presented a 31% open porosity and the SEM micrographs showed a fine interconnected porosity. (author)
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Directory of Open Access Journals (Sweden)
A. Ríos Zambudio
2004-10-01
servicios quirúrgicos. Si analizamos las facilidades que tienen los residentes para realizar actividades científicas, el 55% refieren que sólo con determinados adjuntos, y el 21% que ninguna. La insatisfacción con la formación investigadora aumenta conforme aumenta el año de residencia. En cuando al área troncal de la especialidad, se observa que realizan más tesis los residentes de las áreas quirúrgicas, y que los de áreas centrales refieren menos facilidades. Por último, si se valora la influencia que estas variables pueden tener en la satisfacción general del residente con su residencia, se observa que son factores significativos de insatisfacción. Conclusiones: la mayoría de los residentes están insatisfechos con su formación científica y tienen relativamente pocas facilidades para poder desarrollarla, lo cual se plasma en un escaso número de trabajos científicos y tesis doctorales.
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Energy Technology Data Exchange (ETDEWEB)
Paris, Alexandre Gellert
2007-07-01
In the last few years, the Kyoto Protocol had been a subject very debated, at first, in a restricted niche, manly academics and professionals related to the area of climate changes. On 16th February 2005 the Kyoto Protocol entered into force and with this a lot of publicity all over the world, so today is common to hear about it at the mass communications media. The extension of the subject is broad, this work discuss the utilization of one the Kyoto's flexibility mechanisms, to contribute to financing the use of the landfill gas in the solid oxide fuel cells. Among the three mechanisms presented in the Kyoto Protocol, the clean development mechanism (CDM) in article 12, is the only one that can be implemented by non-Annex I countries, the case of Brazil. In other hand, the issue of solid waste in Brazil is critical. Even being illegal, most of the solid waste goes to uncontrolled areas in open air places 'lixoes', causing degradation of the environment and the communities around this areas, and also emission of green house gases (GHG), deregulating the global climate system. Decontaminate this areas and the construction of landfills to replace than, considering the landfill as a bioreactor, and the utilization of the biogas to generate power can improve nowadays picture that we are facing. The utilization of an innovative alternative technology as the solid oxide fuel cell (SOFC) instead the conventional technologies will be more efficient and environmentally better. Among other barriers the cost is pointed as the biggest. In this context, the SOFC is the most expensive fuel cell, so the utilization of CDM can contribute to finance the application of this technology. Scenarios were made of 250 kW, 500 kW, 1,000 kW, 5,000 kW and 10,000 kW of installed power using biogas from the Municipal Landfill of Santo Andre. The calculations of the emission factor were done ex ante and ex post according to ACM0002. Comparing the costs of the installed power studied and the calculation of the emission reduction, a potential income, the costs are superior, however, other incomes from the selling of energy and the disposal of solid waste most be taken into account in the process of decision of this type of projects. (author)
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Energy Technology Data Exchange (ETDEWEB)
Morales A, E.
2008-07-01
Bromodeoxyuridine (BrdU) has been shown to have a radiosensitizing effect, and its incorporation into DNA prior to administration of a bone-seeking radiopharmaceutical could increase the efficiency of bone marrow ablation, and even increase the specificity of radiation exposure for therapeutic purposes. The aim of the present study was to determine the effect of BrdU incorporation into DNA on the genotoxic and cytotoxic effects of samarium-153 ethylenediaminetetra-methylene phosphonate ({sup 153}Sm-EDTMP) in murine bone marrow cells. BALB/c male mice (N = 5 in each experiment) were treated with one of the following substances: a) BrdU (0.25 mg/g) b) {sup 153}-EDTMP (11.5 +- 3 MBq) c) BrdU (0.25 mg/g) plus {sup 153}Sm-EDTMP (11.5 +- MBq), there was also an untreated control. Cytotoxicity and genotoxicity were established by time-response and absorbed dose-response curves of polychromatic erythrocyte (PCE) and micro nucleated polychromatic erythrocyte (MN-PCE) frequencies, respectively, in murine peripheral blood samples in vivo. The significance of the differences between groups was determined by a variation of Dunett test for multiple groups and different-sized groups of a student test. Beta-absorbed dose fractions obtained from MNCP4B Monte Carlo computer code were used for mice bone marrow dosimetry calculations. At an average radiation absorbed dose of 0.38 Gy, 0.56 Gy and 0.82 Gy at 24, 40 and 72 h respectively, cells from animals treated with {sup 153}Sm-EDTMP showed a clear and significant induction of MN-PCE after 24 h, with the maximum response at 40 h, however, cells from group treated with BrdU plus {sup 153}Sm-EDTMP paradoxically showed MN-PCE frequencies only slightly higher than the control at the same absorbed dose. Treatment with {sup 153}Sm-EDTMP caused a slight reduction in PCE frequency, but exposure to BrdU or BrdU plus {sup 153}Sm-EDTMP induced a substantial and significant reduction in PCE frequency from 32 h to the end of the experiment (72 h). The PCE frequencies in the BrdU pretreated and irradiated group were consistently lower than in the BrdU control group, and the difference was significant at the final scored times in the experiment. These effects could be explained by lethal lesions of the accumulation of sublethal damage induced by the irradiation of BrdU-substituted DNA, where this lesion is not easily repaired and subsequently does not permit cell division or micronucleus formation. This research shows the increasing of cytotoxicity when BrdU was administered before the {sup 153}Sm-EDTMP treatment. Further studies are required in order to explore the utility of this strategy for bone marrow ablation or therapy in humans. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Paris, Alexandre Gellert
2007-07-01
In the last few years, the Kyoto Protocol had been a subject very debated, at first, in a restricted niche, manly academics and professionals related to the area of climate changes. On 16th February 2005 the Kyoto Protocol entered into force and with this a lot of publicity all over the world, so today is common to hear about it at the mass communications media. The extension of the subject is broad, this work discuss the utilization of one the Kyoto's flexibility mechanisms, to contribute to financing the use of the landfill gas in the solid oxide fuel cells. Among the three mechanisms presented in the Kyoto Protocol, the clean development mechanism (CDM) in article 12, is the only one that can be implemented by non-Annex I countries, the case of Brazil. In other hand, the issue of solid waste in Brazil is critical. Even being illegal, most of the solid waste goes to uncontrolled areas in open air places 'lixoes', causing degradation of the environment and the communities around this areas, and also emission of green house gases (GHG), deregulating the global climate system. Decontaminate this areas and the construction of landfills to replace than, considering the landfill as a bioreactor, and the utilization of the biogas to generate power can improve nowadays picture that we are facing. The utilization of an innovative alternative technology as the solid oxide fuel cell (SOFC) instead the conventional technologies will be more efficient and environmentally better. Among other barriers the cost is pointed as the biggest. In this context, the SOFC is the most expensive fuel cell, so the utilization of CDM can contribute to finance the application of this technology. Scenarios were made of 250 kW, 500 kW, 1,000 kW, 5,000 kW and 10,000 kW of installed power using biogas from the Municipal Landfill of Santo Andre. The calculations of the emission factor were done ex ante and ex post according to ACM0002. Comparing the costs of the installed power studied and the calculation of the emission reduction, a potential income, the costs are superior, however, other incomes from the selling of energy and the disposal of solid waste most be taken into account in the process of decision of this type of projects. (author)
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A. Cilla; J. M. Laparra; A. Alegria; R. Barbera
2011-01-01
Introduction: Fruit beverages are commonly supplemented with milk, vitamins and/or minerals in order to improve their healthy effects by providing some bioactive components that can act additively or synergistically against oxidative stress. Aims: To test whether iron, zinc, and milk added to fruit beverages do not affect the cytoprotective effect against oxidative damage to Caco-2 cells through GSH-related enzymes induction and cell cycle progression preservation, in comparison with non-supp...
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Energy Technology Data Exchange (ETDEWEB)
Dias, Ricardo Rodrigues
2009-07-01
In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H{sub 2}PtCl{sub 6}.6H{sub 2}O (Aldrich), SnCl{sub 2}.2H{sub 2}O (Aldrich),and RhCl{sub 2}.XH{sub 2}O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 deg C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2θ = 40{sup 0}, 47{sup 0}, 67{sup 0} and 82{sup 0}, which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 2–3 nm. For PtSn/C and PtSnRh/C two additional peaks were observed at 2θ = 34{sup 0} and 52{sup 0} that were identified as a SnO{sub 2} phase. PtSn/C (50:50) and PtSnRh/C (50:40:10) electrocatalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature PtRu/C, PtSn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 deg C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance. (author)
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Energy Technology Data Exchange (ETDEWEB)
Dias, Ricardo Rodrigues
2009-07-01
In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H{sub 2}PtCl{sub 6}.6H{sub 2}O (Aldrich), SnCl{sub 2}.2H{sub 2}O (Aldrich),and RhCl{sub 2}.XH{sub 2}O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 deg C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2{theta} =40 deg, 47 deg, 67 deg and 82 deg, which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 2-3 nm. For Pt Sn/C and PtSnRh/C two additional peaks were observed at 2 = 34 deg and 52 deg that were identified as a SnO{sub 2} phase. Pt Sn/C (50:50) and PtSnRh/C (50:40:10) electro catalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature Pt Ru/C, Pt Sn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 deg C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance. (author)
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Energy Technology Data Exchange (ETDEWEB)
Owaki, K; Nakamura, T [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)
1962-04-15
succinctement l'interet qu'il y a a utiliser des resistances en parallele avec panneau electroluminescent pour ameliorer les caracteristiques de l'appareil. Ils ont utilise deux types de cellules photoconductrices: une cellule de sulfure de cadmium fritte et une poudre photosensible de sulfure de cadmium, agglomeree a l'aide d'un liant en matiere plastique. Compte tenu des resultats obtenus avec un photomultiplicateur a un seul element, les auteurs ont construit des photomultiplicateurs a deux et a trois etages et fait des experiences destinees a determiner leurs caracteristiques pour diverses resistances en parallele. Avec le photomultiplicateur a trois etages, on a obtenu une amplification d'environ 400 pour un rayonnement d'entree de 0,3 rlx; ces resultats permettent de supposer qu'il serait possible d'obtenir une plus forte amplification pour un rayonnement d'entree plus faible. Les auteurs estiment que les resultats de leurs experiences seront applicables aux renforcateurs d'images a cristal, lorsqu'on aura mis au point une construction appropriee. (author) [Spanish] En los ultimos anos se han publicado varios trabajos sobre intensificacion de la luminosidad de las imagenes mediante el empleo de intensificadores en estado solido, usando fosforos electroluminiscentes y sustancias fotoconductoras, lo que constituye una aplicacion importante de la electronica del estado solido. Es conveniente e importante el uso del intensificador de estado solido para amplificacion luminosa. El objeto del presente trabajo experimental es obtener una mayor amplificacion acoplando el intensificador en varias etapas en cascada. Los autores comienzan describiendo las caracteristicas electricas y opticas de un elemento intensificador y examinan brevemente la ventaja de emplear una resistencia montada en paralelo con la pantalla electroluminiscente, para mejorar las caracteristicas de esta. En los experimentos se utilizaron dos tipos de celulas fotoconductoras : una de CdS sinterizado y otra de Cd
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Energy Technology Data Exchange (ETDEWEB)
De Brouckere, L; Van Leemput, R; Stein, R [Laboratoire de Chimie Generale II, Universite Libre de Bruxelles (Belgium)
1962-03-15
'acetone. On a utilise des chambres de diffusion analogues aux osmometres a cellules jumelles. Des membranes de cellophane de permeabilite 6,7 {center_dot} 10{sup -5} h{sup -1} a 30,6 {center_dot} 10{sup -5} h{sup -1} separaient la solution du solvant. On a constate: a) Qu'avec l'appareil utilise dans les experiences de diffusion, il fallait environ deux cents heures pour atteindre un etat d'equilibre ou un etat stationnaire; b) Que la fraction de polymere se diffusant a travers la membrane dans un temps donne etait independante de la concentration; c) Que la quantite de polymere diffuse variait en fonction de la permeabilite de la membrane; d) Qu'il se produisait une adsorption pratiquement irreversible du polymere sur la membrane (30 a 40 {mu}g/cm{sup 2}). (author) [Spanish] Las dos principales fuentes de error cuando se estudian fenomenos osmoticos con polimeros de elevado peso molecular son: a) la difusion de polimeros de bajo peso molecular a traves de la membrana; b) la adsorcion de polimeros en la membrana. Los metodos que emplean trazadores radiactivos para la investigacion de estos dos fenomenos ofrecen ventajas decisivas sobre los procedimientos gravimetricos clasicos, que son mucho menos sensibles. El polimero empleado por los autores consistio en una muestra heterodispersa de policloroacrilato de butilo obtenido por el oracion ionica del poliacrilato de butilo con {sup 36}Cl. Este polimero se utilizo disuelto en acetona. Los autores emplearon camaras de difusion, semejantes a osmomotros de celulas gemelas. La solucion quedaba separada del disolvente por membranas de celofan de permeabilidades de 6,7 x 10{sup -5} h{sup -1} a 30,6 x 10{sup -5} h{sup -1}. Han llegado a las conclusiones siguientes: a) con el aparato empleado en los experimentos de difusion, se precisan unas 200 horas para alcanzar un estado de equilibrio o un regimen estacionario; b) la fraccion de polimero que difunde a traves de la membrana en un tiempo determinado es independiente de la
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Células madre y terapia celular
Directory of Open Access Journals (Sweden)
Elso Manuel Cruz Cruz
2015-03-01
Full Text Available Una célula madre (CM o célula troncal es aquella capaz de dividirse indefinidamente y diferenciarse a distintos tipos de células especializadas, no sólo morfológica sino también funcionalmente. Las células madre pueden clasificarse atendiendo a su origen en células madre adultas (CMA y células madre embrionarias (CME. Por sus características, las CM tienen potencialidades para diversos usos en la práctica clínica. La primera es como vehículo terapéutico de genes, en el caso de enfermedades monogénicas o incluso como vehículo de terapias antitumorales o antiangiogénicas. La segunda y principal aplicación es, aprovechando su potencial de diferenciación, en la regeneración de tejidos destruidos o dañados, como terapia de reemplazo celular o medicina regenerativa. En esta área se están desarrollando trabajos de investigación donde se busca reemplazar células dañadas por otras que restituyan la función normal de los tejidos u órganos; en enfermedades como: diabetes mellitus, enfermedades cardiovasculares, enfermedad de Parkinson y enfermedades de células sanguíneas. Actualmente existen muchas investigaciones enfocadas a descubrir células progenitoras que sirvan como banco de células para usos terapéuticos. Se reporta el empleo de varias estrategias, las que incluyen: terapias celulares derivadas de células autólogas; terapias celulares derivadas de líneas celulares establecidas desde una variedad de CM que incluyen MO, cordón umbilical, CME, así como células de tejidos y órganos de animales genéticamente modificados. Las principales aplicaciones se realizan con CM de la médula ósea (MO, ya que esta es un recurso celular propio, accesible y abundante para la terapia celular. (1 En la MO existe un grupo heterogéneo de CMA; además de las hematopoyéticas (CMH están las: endoteliales, mesenquimales (CMM, de la población lateral, progenitoras adultas multipotentes, ovales y también células madre muy peque
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Energy Technology Data Exchange (ETDEWEB)
Gonzalez B, F
2004-07-01
In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)
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Clode, W. H.; Perez Fernandez, M. A.; Baptista, A. M. [Comissao de Estudos de Energia Nuclear do Instituto de Alta Cultura, Lisbon (Portugal); Simao Rodrigues, M.; Murteira, M. A. [Instituto Portugues de Oncologia, Lisbon (Portugal)
1964-10-15
estudios los autores han llegado a la conclusion de que ciertas regiones del estomago normal desempefian un papel importante en el metabolismo del yodo. La localizacion de las zonas en que la concentracion de radiactividad es mas elevada indica que la excrecion de yodo puede ser regida por varios mecanismos. Estas observaciones corroboran los resultados obtenidos por otros investigadores con metodos diferentes. La exploracion efectuada 24 h despues de administrar {sup 131}I permitio detectar el cancer del estomago en la mayorla de los pacientes afectados por esa enfermedad. Estos resultados se explican no solo por el hecho de que el yodo se concentra en las celulas tumorales sino tambien porque las paredes del estomago retienen cierta cantidad de este elemento. En la mayor parte de los casos, la concentracion de yodo radiactivo en el tumor no fue superior a la observada en aquellas regiones de la mucosa gastrica en que se produce una absorcion incrementada de este elemento. (author) [Russian] Avtory izuchali lokalizaciju joda v zheludke posle vnutrivennoj in{sup e}kcii iodida, mechennogo jodom-131, ispol'zuja dlja jetogo vysokokontrastnuju sistemu fotoskennirovanija. Issledovanie provodilos' cherez razlichnye promezhutki vremeni posle in{sup e}kcii (obychno cherez 2, 24 i 48 chasov) u bol'nyh, ne stradajushhih nikakimi zheludochnymi zabolevanijami, bol'nyh s rakom zheludka i bol'nyh s pepticheskoj jazvoj. Izuchalos' takzhe raspredelenie radioaktivnogo joda v zheludkah sobaki i cheloveka, udalennyh hirurgicheskim putem v razlichnoe vremja posle in{sup e}kcii radioaktivnogo joda. V udalennyh hirurgicheskim putem zheludkah dlja ob{sup j}asnenija poluchennyh dannyh opredeljalas' udel'naja aktivnost' tkanej, otnosjashhihsja k predstavljajushhim interes oblastjam, obnaruzhen** nym skennirovaniem. Na osnovanii poluchennyh dannyh avtory delajut vyvod, chto v normal'nom zheludke sushhestvujut oblasti, kotorye igrajut osobuju rol' v metabolizme joda. Lokalizacija zon samoj vysokoj
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Energy Technology Data Exchange (ETDEWEB)
Gordon Steel, G. [Physics Department, Institute of Cancer Research, Royal Cancer Hospital, Clifton Avenue, Belmont, Surrey (United Kingdom)
1962-02-15
foie, initialement elevee, diminuait rapidement. A l'aide d'un dispositif permettant de prelever des echantillons de l'eau des tissus faiblement irradies, l'auteur a mesure l'activite specifique de l'eau tritiee dans divers organes. Une heure apres l'injection, la concentration du tritium etait pratiquement uniforme dans tout le corps; mais pendant la periode ou s'etablissait cet equilibre, on a pu constater des gradients considerables dans l'activite specifique de l'eau des tissus. Dans le cas du foie, il s'agissait d'un afflux dans le sang d'eau tritiee provenant de cet organe; pour la rate, les testicules et les muscles, le mouvement etait oriente en sens contraire. Les mesures de la retention du tritium dans l'intestin et la moelle osseuse apres administration de thymidine tritiee ont montre qu'il existe pour les deux tissus consideres un palier initial et que la desintegration ulterieure comporte deux exponentielles predominantes. Dans le cas de la moelle osseuse, l'observation d'un palier est en desaccord avec d'autres travaux publies; il n'est du reste pas observe de palier chez les animaux qui ont ete soumis a une irradiation prolongee. (author) [Spanish] La memoria describe los resultados de investigaciones del catabolismo de la timidina tritiada en la rata durante el periodo de su fijacion inicial en los tejidos, y de la retencion de celulas marcadas con tritio en el intestino y en la medula osea hasta 16 dias despues de la marcacion. Durante la hora que sigue a la inyeccion de timidina tritiada, la concentracion de tritio no volatil crece hasta alcanzar el valor de saturacion en la mayoria de los tejidos, pero la concentracion hepatica desciende rapidamente desde un nivel inicial elevado. El autor midio la actividad especifica del agua tritiada de varios organos, empleando para ello un dispositivo que permite extraer en frio muestras de agua de los tejidos. Una hora despues de la inyeccion, la concentracion de tritio era casi uniforme en toda el agua del
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Directory of Open Access Journals (Sweden)
A. Segorbe Luis
1997-09-01
em que decorre um processo imunoinflamatório.Tal ocorrência, ao ter sido verifieada na pleurisia tuberculosa, vem questionar a noção de que o tráfego linfocitário seja exclusivo de linfócitos efectores e 'memória' quando estão em causa respostas celulares de perfil Th1 na serosa pleural.O facto das células CD45RA encerrarem em si a possibilidade de diferenciação em células efectoras Th 1 ou Th2, é provável que o ambiente citocÃnico existente na pleurisia tuberculosa condicione a sua maturação para celulas Th1. No entanto, sendo conhecida a vocação 'Th2' das células CD45RA+, será também de considerar a sua possÃvel intervenção na produção local de citocinas inibidoras da actividade de clãs Th1. SUMMARY: CD45RA+T CELLS ARE PRESENT IN TUBERCULOUS PLEUÂRAL EXUDATESLymphocyte circulation and diapedesis have as biological aims the insurance of the availability of antigen receptors as well as the functional unification of the various lymphoid compartments. Thus, the probability of a small number of 'naive' cells being able to a encounter their specific antigen epitope is increased and the supply of antigen receptors on 'memory' and effector cells to peripheral tissues is optimized.It is generally accepted that 'naïve' T lymphocytes, virgin in terms of antigenic stimulation, tend to sistematically migrate into secondary lymphoyd tissues (lymph nodes, Peyer patches, tonsils, â¦, where they become 'memory' cells in a milieu differenciated towards antigen presentation. As 'memory' cells, T lymphocytes acquire the capacity to migrate into tertiary lymphoyd compartments (skin, mucosae, â¦. The migration of 'memory' lymphocytes into tissues plays a crucial role in the defense against microbes, namely in the generation of secondary responses.Tuberculous pleurisy occurs as result of a hypersensitivity reaction to mycobacterial antigens. In this form of pleuritis, local responses
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Energy Technology Data Exchange (ETDEWEB)
Machurek, J. E.; Stein, M. H. [Division of Isotopes Development, USAEC, Washington, DC (United States)
1963-11-15
autores comunican los resultados de catorce de esas investigaciones, resumiendo algunos en la monografia y dando mas detalles sobre otros en las actas respectivas. Los temas tratados son los siguientes: 1. Preparacion de combinaciones madera-materiales plasticos utilizando las radiaciones gamma para inducir la polimerizacion. 2. Empleo de las radiaciones beta emitidas por los productos de fision para la hidrogenacion del carbono y sus derivados con miras a la produccion de hidrocarburos liquidos combustibles. 3. Preparacion de semiconductores en los cuales las impurezas se distribuyen con arreglo a un esquema espacial predeterminado, con ayuda de transmutaciones neutronicas. 4. Polimerizacion radioinducida del etileno y sus copolimeroe. 5. Estudios basicos de los mecanismos y la cinetica de las reacciones radioinducidas. 6. Aspectos radioquimicos de la fluoracion de diversos compuestos aromaticos. 7. Empleo de monomeros polifuncionales para acrecentar la radiorreticulacion en el polietileno, el polipropileno, el poliisobutileno y el acetato de celulosa. 8. Efectos de la turgencia, tension y temperatura sobre las propiedades fisicas y quimicas de los polimeros producidos con ayuda de las radiaciones. 9. Influencia de los factores estructurales sobre las modificaciones radioinducidas en polimeros que conducen a la copolimerizacion por injerto. 10. Utilizacion de las radiaciones nucleares para modificar las propiedades de los materiales textiles. 11. Reacciones radioinducidas en las que se utiliza el cripton-85. 12. Preparacion de un ''Manual de Radiaciones''. 13. Empleo de enlaces organometalicos en la dosimetria de radiaciones gamma de elevada intensidad. 14. Preparacion de un dosimetro de celula solar. (author) [Russian] V sootvetstvii s programmoj issledovanij radiatsionnykh protsessov Komissii po atomnoj ehnergii SSHA byli provedeny obshirnye izyskaniya. Glavnaya tsel' ehtikh issledovanij sostoit v sodejstvii razrabotke tekhnologii, kotoraya obespechila by ehffektivnoe
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Energy Technology Data Exchange (ETDEWEB)
Sodee, D. B. [Doctors Hospital and Renner Clinic Foundation, Cleveland Heights, OH (United States)
1964-10-15
casos. El carcinoma mas pequeno que no pudo visualizarse estaba ocultado por el higado hipertrofiado. La exploracion pancreatica permite tambien confirmar la pancreatitis aguda y cronica, ya que las celulas lesionadas no concentran la selenometionina-{sup 75}Se. El autor trata ademas de la concentracion selectiva de la selenometionina{sup 75}Se en el tejido paratiroideo. Con la misma tecnica de expioracion se han visualizado adenomas paratiroideos en un pequeno grupo de enfermos de hiperparatiroidismo. La fotoexploracion del pancreas es ya una tecnica de uso corriente; actualmente se estudia la posibilidad de una fotoexploracion de la paratiroides. Debido a la mayor importancia medica atribuida a organos que antes no podian visualizarse con las tecnicas radiograficas tradicionales, la exploracion selectiva de organos por medio de compuestos marcados, elegidos segun sus propiedades bioquimicas, va adquiriendo cada vez mayor importancia. (author) [Russian] Nedavno bylo pokazano, chto fotoskennirovanie podzheludochnoj zhelezy s pomoshh'ju selenometionina, mechennogo {sup 75}Se , javljaetsja prakticheskim metodom. U 90%iz 100 bol'nyh, u kotoryh bylo polucheno 250 podobnyh fotoskennogramm, mozhno bylo otchetlivo videt' podzheludochnuju zhelezu. Bylo obnaruzheno, chto fiziologicheskaja stimuljacija podzheludochnoj zhelezy javljaetsja glavnym faktorom koncentracii selenometionina -Se15 v podzheludochnoj zheleze. Za chas do vnutrivennogo vvedenija v organizm 3-4 mkk/kg selenometionina-Ze75 s pomoshh'ju 30 grammov belkovoj pishhi byla nachata fiziologicheskaja stimuljacija podzheludochnoj zhelezy. Cherez 15 minut byla dostignuta nepreryvnaja stimuljacija podzheludochnoj zhelezy putem vvedenija cherez rot 900 mkg gidrohlorida glutaminovoj kisloty. Do skennirovanija podzheludochnoj zhelezy nad oblast'ju pecheni, predvaritel'no opredelennoj pri skennirovanii s pomoshh'ju zolota-198, byl pomeshhen izognutyj zashhitnyj jekran iz svinca razmerom 0,9 sm, Jetot jekran blokiruet
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Energy Technology Data Exchange (ETDEWEB)
Valgode, Flavia Gomes Silva
2015-11-01
Differentiated thyroid cancer (DTC) represents about 90% of thyroid malignancies with increasing incidence in the recent decades. Treatment modalities include thyroidectomy, {sup 131}I therapy (with or without r-hTSH), radio and chemotherapy. Little is known about the effects of these treatments at the cellular level. This work was proposed in order to assess to what extent radioiodine therapy can cause damage in peripheral lymphocytes of patients with DTC, preceded or not by r-hTSH, taking into account acute, slow and dosimetric effects of {sup 131}I (in vivo study). An in vitro study was also carried out on thyroid tumor target cells (WRO) by cytotoxicity and genotoxicity analysis and radioiodine uptake. For this, blood samples from patients divided into two groups (group A, r-hTSH + {sup 131}I and group B,{sup 131}I only) were collected before, 24 hours, 1 week, 1 month and 1 year after {sup 131}I administration for aberration chromosome analysis (CA). A dose-response curve for {sup 131}I in vitro was developed for estimating the absorbed dose in patients, comparing the dicentric frequencies obtained in vitro with in vivo data by Monte Carlo program. Radioiodine therapy induced an increase in the number of CA in lymphocytes of patients peaking 24 hours after treatment, with gradual decline over time and with more chromosomal damage in group B than in group A, reaching baseline levels one year after radioiodine administration. The frequency of dicentric found inpatient lymphocytes, 24h after treatment, was equivalent to that induced in vitro (0.354 ± 0.153 MBq / mL for group A and 0.309 ± 0.154 MBq / mL for group B), which corresponds to absorbed doses of 0.8 ± 0.3 Gy and 0.7 ± 0.3 Gy for groups A and B, respectively, with no significant difference between the groups. WRO cells showed a cell cycle relatively slow: 96,3h with an unstable karyotype. The genotoxic test showed a relatively high radioresistance (0.07 to 3.70 MBq/mL), with no statistical significance, with or without r-hTSH. However, the cytotoxic assay, showed a tendency to decrease at higher concentrations of 1.85 (p <0.05) and 3.70 MBq/ml (p <0.01) only in the presence of r-hTSH, coincident with the highest level of uptake. WRO cells were also relatively radioresistant to external irradiation of {sup 60}Co in the range of 0.2-8.3 Gy, with a gradual decrease in function of time for higher doses (10,20 and 40Gy).The data obtained showed little cytogenetic damage in patients upon therapeutic exposure, suggesting a safe and effective treatment for both groups of patients. Patients in group A, however, had a better quality of life by using r-hTSH. In vitro studies with internal ({sup 131}I) and external ({sup 60}Co) irradiation, with or without r-hTSH, point to the need for an alternative therapeutic strategy to overcome the loss of ability of thyroid cells (WRO) to concentrate radioiodine, which is responsible for the failure of radioiodine therapy in patients with DTC. (author)
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Energy Technology Data Exchange (ETDEWEB)
Rojas C, E. L.; Perez A, M., E-mail: leticia.rojas@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)
2011-11-15
The necessity to design innovative treatments and to diagnose the cancer early, has taken to investigate therapies at cellular and molecular level. The design of appropriate radio-molecules to these therapies makes necessary to characterize in way exhaustive radionuclides that they are of accessible production in our country and to study as distributing the dose at cellular level with bio-molecules glued them. In this context, was realized the present work. Using Monte Carlo simulation, the energy deposited in a geometric model of cells of breast cancer was obtained, MDA-MB231, due to different radionuclides. The energy deposited in the nucleus was evaluated, in the cytoplasm and in the membrane of the cell, using the simulation code Monte Carlo Penelope 2008. A punctual source was simulated in the center of the cell nucleus. In each case all the emissions of each radionuclide majors to 400 eV were simulated. The energies deposited by disintegration in the nucleus, cytoplasm, membrane of the cell and in a sphere of 2 cm surrounding the source (in eV) were: 4.30E3, 4.85E2, 1.07E2 and 3.29E4, correspondingly, for the {sup 111}In; 4.46E3, 3.76E3, 1.26E3 and 1.33E5 for the {sup 177}Lu and; 2.12E3, 2.58E2, 9.33E1 and 1.88E4 for the {sup 99m}Tc. We can conclude that if the union of these radionuclides happens to a compound that was internalized to the cell nucleus, the best for therapy at this level is the conjugate with the {sup 177}Lu, followed by that with {sup 111}In and in third place that with {sup 99m}Tc. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Jones, R. K.; Engel, R. E.; Godden, W. R. [Kirtland AFB, New Mexico (United States)
1964-05-15
atteints presentaient un gonflement endothelial extremement marque, mais leur tunique moyenne ne presentait pas de modifications essentielles. On notait egalement une hemorragie peribronchiale au niveau des arteres pulmonaires atteintes. La pathogenese de ces alterations semble etre liee primitivement a une deterioration de l 'endothelium provoquee par les neutrons de fission puises; un facteur complementaire est vraisemblablement la thrombocytopenie, puisqu'on a constate que le nombre de megacaryocytes de la moelle etait inversement proportionnel a'la gravite de l'hemorragie intiapulmonaire. (author) [Spanish] La comparacion de las alteraciones de los tejidos en perros expuestos a rayos X de 250 kVp y a un haz pulsado de neutrones de fision, efectuada anteriormente en el mismo laboratorio, revelo que las reacciones son similares en lineas generales. Sin embargo, los pulmones de los animales expuestos a neutrones de fision son mucho mas propensos a las hemorragias peribronquiales y perivasculares. Los autores han intentado definir la patogenesis de esta lesion exponiendo 5 sabuesos a una dosis de 400 rad (dosis maxima admisible) de un haz de neutrones rapidos procedentes de un reactor tipo GODIVA (sin reflector) y sacrificando luego los animales a intervalos regulares. Cinco dias despues de la irradiacion, se manifestaron serias alteraciones patologicas constituidas por pequenas hemorragias pulmonares esporadicas en la periferia. Hacia el noveno dia, el numero de estas hemorragias aumenta progresivamente. Los cambios mas notables ocurren a los 13 dias y consisten en extensas hemorragias perivasculares en torno a las ramas de la arteria pulmonar, desde el hilio hasta la superficie de la pleura. Las primeras modificaciones histologicas en los pulmones se observaron a los cinco dias: se trata de zonas focales bien delimitadas de congestion alveolar, acompanadas por una hinchazon de las celulas del endotelio capilar y una leve extravasacion alveolar de los hematies. Estos
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Energy Technology Data Exchange (ETDEWEB)
Stehlik, G.; Kaindl, K. [Institute for Biology and Agriculture, Reaktorzentrum, Seibersdorf (Austria)
1966-11-15
survie obtenues a des temperatures differentes, on constate que, dans le cas d'une irradiation a une temperature superieure a 40 Degree-Sign C, le traitement simultane produit un effet synergique prononce, qui atteint deux ordres de grandeur pour 150 krad. En partant de ces resultats, on procede actuellement a une etude des possibilites techniques de ce traitement sur des jus de pomme et de raisin. (author) [Spanish] Uno de los principales temas de investigacion incluidos en el programa internacional relativo a la irradiacion de frutas y zumos de fruta que se viene ejecutando en Seibersdorf se refiere al problema de la radio- sensibilizacion de microorganismos. Para estudiar los efectos del tratamiento termico y del tratamiento por irradiacion sobre la supervivencia de las celulas de levadura (formacion de colonias), se sometio a un tratamiento combinado de aplicacion de calor y de irradiacion gamma (fuente: {sup 60}Co), al comienzo de su fase de desarrollo logaritmico, una cepa de elevada radiorresistencia -Saccharomyces cerevisiae var. ellipsoideus - cultivada en un medio nutritivo semisintetico. El calor se aplico inmediatamente antes de la irradiacion, durante esta o inmediatamente despues. Las temperaturas estuvieron comprendidas entre 20 y 52,5 Degree-Sign C. La irradiacion se realizo con dosis de hasta 0,3 x 10{sup 6} rad, en un tubo de vidrio, bien aireado. El efecto inhibidor de este tratamiento combinado depende del orden en que se suceden la aplicacion del calor y la irradiacion, habiendose llegado a las siguientes conclusiones: la combinacion mas eficaz consiste en simultanear el tratamiento termico con el tratamiento por irradiacion; esta combinacion resulta menos eficaz cuando la irradiacion a la temperatura ambiente tiene lugar a continuacion del tratamiento termico; la combinacion de eficacia minima consiste en proceder al tratamiento termico despues de haberse efectuado la irradiacion a la temperatura ambiente. El tratamiento termico combinado con la
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Energy Technology Data Exchange (ETDEWEB)
Jee, W. S.S.
1964-10-15
distribucion completa en el espacio y en el tiempo de una dosis en un tejido oseo dado representa una labor improba. La distribucion microscopica de los radionuclidos osteofilos (radio-226, estroncio-90, plutonio-239 y radiotorio-228) en el esqueleto ilustran nitidamente la complejidad del problema. Se describen, con referencia al radio y al plutonio, las caracteristicas de la dosis inicial de irradiacion y las caracteristicas alteradas con el transcurso del tiempo, insistiendose particularmente en la falta de uniformidad de la distribucion de la dosis en los huesos y en diferentes lugares dentro de' un tejido oseo determinado. Por ejemplo, los depositos superficiales maximos de plutonio en la trabecula vertebral son 1,5 veces mas activos que las concentraciones maximas en la trabecula de la metafisis femoral. Las razones entre las dosis provenientes de depositos superficiales de plutonio en diversos lugares del femur distal son: trabecula de la metafisis, 3; endostio, 2,6; trabecula de la epffisis, 1,5; conductos de Havers, 1,2; periostio, 1. El deposito superficial maximo localizado en las trabeculas vertebrales es de 35 a 66 veces mayor que la dosis media calculada que corresponde a la cantidad retenida en todo el organismo. La alteracion de la localizacion inicial no uniforme del radio y del plutonio con el tiempo se examina en relacion con el caracter de la renovacion celular del tejido oseo y con la perdida del radionuclido por intercambio a largo plazo. Por ultimo, un ejemploi de medicion de las dosis locales de irradiacion debidas al plutonio y al radio, en el que se tiene en cuenta el volumen de las celulas irradiadas, que se relaciona con la cantidad retenida en todo el organismo y con la incidencia de tumores, se utiliza para evaluar la toxicidad del plutonio referida al radio y demostrar la utilidad de algunos conocimientos acerca de la distribucion microscopica de la dosis de irradiacion. (author) [Russian] Proizvodilos' issledovanie detal'nogo mikroskopicheskogo
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Energy Technology Data Exchange (ETDEWEB)
Moskalev, Ju. I.; Petrovich, I. K.; Strel' cova, V. N.
1964-03-15
frecuencia y rapidez de formacion de tumores en la rata, en funcion de la dosis aplicada y del tiempo transcurrido a partir de' la irradiacion. En el experimento con neutrones utilizaron 573 ratas blancas y en el experimento con protones, 490. Expusieron los animales a dosis neutronicas de 8,5 a 510 rad, y dosis protonicas comprendidas entre 28 y 1008 rad. Tanto para los neutrones rapidos como para los protones, establecieron el valor de la dosis efectiva aguda, subaguda y cronica. La DL{sup 30}{sub 50} para los neutrones asciende a 408 rad y a 600 rad para los protones; las respectivas dosis DL{sup 120}{sub 50} son 380 rad y 600 rad. Los autores estudiaron las leyes que rigen la mortalidad de los sujetos en experimentos breves y prolongados. Demuestran que la sobrevivencia de los mismos, cuando se ios irradia con neutrones rapidos, es independiente del sexo. La forma de la curva dosis/efecto para los diversos Indices de la sangre periferica no solo depende de la radiosensibilidad de las celulas sanguineas correspondientes, sino tambien del perfodo de observacion. Puede sufrir modificaciones sensibles en funcion del tiempo para un mismo indice. Algun tiempo despues de la irradiacion, tanto con neutrones rapidos como con protones, se observan en las ratas tumores de caracter benigno o maligno en diversos tejidos, entre ellos en los de los arganos hematopoyeticos, las glandulas mamarias, la hipofisis, el utero, los ovarios, la prostata, los testiculos, la tiroides, el timo y el pancreas, las glandulas suprarrenales, el higado, los rinones, los pulmones, el tracto gastrointestinal, el tejido hipodermico, los ganglios linfaticos, la vejiga, etc. La frecuencia total de los tumores y el numero de casos de formacion multicentrica de neoplasias es de 2 a 3 veces mayor en las hembras que en los machos. La dosis tumorigena minima en las glandulas mamarias, en la irradiacion neutronica, parece ser algo inferior a 42,5 rad. La frecuencia maxima de los tumores de la hipofisis se observa
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Energy Technology Data Exchange (ETDEWEB)
Joftes, D. L. [New England Deaconess Hospital, Boston, MA (United States)
1963-09-15
decrit en detail les methodes recommandees ainsi que le materiel necessaire, qui est simple et dont disposent generalement les laboratoires. (author) [Spanish] Las nuevas tecnicas autorradiograficas simplificadas requieren cierto esfuerzo pero permiten obtener una gran sensibilidad y exactitud al nivel microscopico en el estudio de los insecticidas marcados con uno o dos radioisotopos, y, en particular, en el de la absorcion, traslocacion, metabolismo y determinacion de residuos en plantas, insectos y los animales.' Con ellas se pueden estudiar tambien la fisiologia y la bioquimica de los insectos irradiados. Se estan investigando con timidina tritiada los efectos de las radiaciones sobre los organos reproductores. Las tecnicas de recuento dan informacion general sobre la presencia y la cantidad de los radioisotopos, mientras que la autorradiografia proporciona datos sobre el lugar exacto de fijacion en los tejidos e incluso en partes de la celula. Este poder de resolucion se alcanza con preparados histologicos ordinarios que pueden conservarse, contrariamente a lo que sucede con las tecnicas de recuento que exigen, si se quiere lograr mayor exactitud, la destruccion de la muestra. La autorradiografia corriente es particularmente util para analizar por metodos muy sencillos fracciones de microcurie de emisores muy debiles como el radiocarbono ( {sup 14}C) y el tritio ({sup 3}H), mientras que las tecnicas de recuento requieren en estos casos un instrumental muy complicado y costoso. Esta tecnica no impone limitacion alguna en cuanto a los isotopos que pueden emplearse como indicadores, porque la emulsion nuclear registra incluso las radiaciones del tritio y del {sup 14}C. En realidad, el tritio y el {sup 14}C (que son convenientes puesto que casi todos los insecticidas contienen carbono o hidrogeno) tienen la ventaja de dar autorradiografias'de elevado poder de resolucion y, como son de periodo largo, permiten tiempos de exposicion muy prolongados. Estos tiempos de